ABSTRACT

As part of the systematic study of the tribes Ditaxeae and Adelieae (Acalyphoideae-Euphorbiaceae), here we compile and present a taxonomic synopsis for the South American taxa of Argythamnia, Chiropetalum, and Philyra. We recognize 22 species for Argythamnia, including one herein described as a new species, 20 species and one variety for Chiropetalum, and a single species for Philyra. We also designate 22 lectotypes, a new synonymization and a status novum, in addition to keys for each genus, distribution maps for all taxa, analysis of collection density in South America for each genus, and taxonomic and ecological comments for all taxa.

Keywords:
Acalyphoideae; Adelieae; Ditaxis; Ditaxineae; nomenclatural novelties; taxonomy

Introduction

Euphorbiaceae are distributed worldwide and are one of the largest families of Angiosperms (APG IV 2016APG IV. 2016. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV. Botanical Journal of the Linnean Society 181: 1-20. doi: 10.1111/boj.12385
https://doi.org/10.1111/boj.12385... ), circumscribed with four subfamilies, 218 genera and approximately 6300 species (Radcliffe-Smith 2001Radcliffe-Smith A. 2001. Genera Euphorbiacearum. London, Royal Botanic Garden Kew.; Webster 2014Webster GL. 2014. Euphorbiaceae. In: Kubitzki K (ed.). The Families and Genera of Vascular Plants. Flowering plants. Eudicots. Malpighiales. Berlin, Springer. v. 11, p. 51-216.; APG IV 2016APG IV. 2016. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV. Botanical Journal of the Linnean Society 181: 1-20. doi: 10.1111/boj.12385
https://doi.org/10.1111/boj.12385... ). The pantropical subfamily Acalyphoideae Beilschm. is composed of 99 genera and 1865 species (APG IV 2016APG IV. 2016. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV. Botanical Journal of the Linnean Society 181: 1-20. doi: 10.1111/boj.12385
https://doi.org/10.1111/boj.12385... ). In the classification proposed by Webster (1994Webster GL. 1994. Synopsis of the genera and suprageneric taxa of Euphorbiaceae. Annals of the Missouri Botanical Garden 81: 33-144. ; 2014Webster GL. 2014. Euphorbiaceae. In: Kubitzki K (ed.). The Families and Genera of Vascular Plants. Flowering plants. Eudicots. Malpighiales. Berlin, Springer. v. 11, p. 51-216.) and Radcliffe-Smith (2001Radcliffe-Smith A. 2001. Genera Euphorbiacearum. London, Royal Botanic Garden Kew.), the Acalyphoideae genera Argythamnia P.Browne, Caperonia A.St.-Hil., Chiropetalum A.Juss., Ditaxis Vahl ex A.Juss., and Philyra Klotzsch were circumscribed in the subtribe Ditaxinae Griseb. In the recent phylogenetic study of Külkamp et al. (2023a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.), Ditaxinae and Ditaxis proved to be paraphyletic, so Ditaxis was synonymized under Argythamnia, and the subtribe was elevated to the rank of tribe (Ditaxeae) with only two genera, Argythamnia and Chiropetalum. Because Philyra emerged as sister to the tribe Adelieae, it was treated in Adelieae as proposed by Jestrow et al. (2008Jestrow B, Proctor G, Francisco-Ortega J. 2008. Lasiocroton trelawniensis (Euphorbiaceae), a critically endangered species from the Cockpit Country of Jamaica, belongs to Bernardia (Euphorbiaceae). The Botanical Review 74: 166-177. doi: 10.1007/s12229-008-9009-5
https://doi.org/10.1007/s12229-008-9009-... ; 2010Jestrow B, Rodríguez FJ, Francisco-Ortega J. 2010. Generic delimitation in the Antillean Adelieae (Euphorbiaceae) with description of the Hispaniolan endemic genus Garciadelia. Taxon 59: 1801-1814. ). Caperonia emerged as the sister clade to the Ditaxeae and Adelieae tribes, so it was circumscribed in the monogeneric tribe Caperoniieae (Külkamp et al. 2023aKülkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.). Even in the new circumscription, some genera are morphologically similar (Argythamnia and Chiropetalum), while others are quite distinct (Philyra). The main diagnostic morphological characteristics of these genera can be compared in Tab. 1 and Fig. 1, based on the present and other studies (Webster 1994Webster GL. 1994. Synopsis of the genera and suprageneric taxa of Euphorbiaceae. Annals of the Missouri Botanical Garden 81: 33-144. , 2014Webster GL. 2014. Euphorbiaceae. In: Kubitzki K (ed.). The Families and Genera of Vascular Plants. Flowering plants. Eudicots. Malpighiales. Berlin, Springer. v. 11, p. 51-216.; Radcliffe-Smith 2001Radcliffe-Smith A. 2001. Genera Euphorbiacearum. London, Royal Botanic Garden Kew.; Külkamp 2020aKülkamp J. 2020a. Ditaxis. In: Flora e Funga do Brasil. Rio de Janeiro, Jardim Botânico do Rio de Janeiro. http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB17557. 20 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... , bKülkamp J. 2020b. Philyra. In: Flora e Funga do Brasil. Rio de Janeiro, Jardim Botânico do Rio de Janeiro . http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB25551. 20 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... , cKülkamp J. 2020c. Caperonia. In: Flora e Funga do Brasil. Rio de Janeiro, Jardim Botânico do Rio de Janeiro . http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB17471. 12 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... ; Külkamp et al. 2020aKülkamp J, Iganci JRV, Cordeiro I. 2020a. Chiropetalum. In: Flora e Funga do Brasil . Rio de Janeiro, Jardim Botânico do Rio de Janeiro . http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB29160. 10 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... , bKülkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.; 2023aKülkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173., bKülkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ).

According to the new classification proposed by Külkamp et al. (2023a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.), Argythamnia increased from 18 to ca. 68 species, extending its distribution from southern North America to Argentina. Its centers of diversity are in southern North America, Central America, the Antilles, and northeastern and central South America (Pax & Hoffmann 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.; O’Donell & Lourteig 1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ; Ingram 1967Ingram J. 1967. A revisional study of Argythamnia subgenus Argythamnia (Euphorbiaceae). Gentes Herbarum 10: 1-38.; Ramírez-Amezcua & Steinmann 2013Ramírez-Amezcua Y, Steinmann VW. 2013. Revisión taxonómica de Argythamnia subgénero Ditaxis (Euphorbiaceae) en México. Botanical Sciences 91: 427-459.; Külkamp 2020aKülkamp J. 2020a. Ditaxis. In: Flora e Funga do Brasil. Rio de Janeiro, Jardim Botânico do Rio de Janeiro. http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB17557. 20 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... ; Külkamp et al. 2020bKülkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.; 2023aKülkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.). The species occur predominantly in seasonally dry environments, such as the arid regions of northern Mexico and the southern United States, and other locals with seasonally dry tropical forests in the Neotropics (O’Donell & Lourteig 1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ; Ramírez-Amezcua & Steinmann 2013Ramírez-Amezcua Y, Steinmann VW. 2013. Revisión taxonómica de Argythamnia subgénero Ditaxis (Euphorbiaceae) en México. Botanical Sciences 91: 427-459.; Külkamp 2020aKülkamp J. 2020a. Ditaxis. In: Flora e Funga do Brasil. Rio de Janeiro, Jardim Botânico do Rio de Janeiro. http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB17557. 20 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... ; Külkamp et al. 2020bKülkamp J. 2020b. Philyra. In: Flora e Funga do Brasil. Rio de Janeiro, Jardim Botânico do Rio de Janeiro . http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB25551. 20 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... ).

Philyra is one of the monospecific genera of Euphorbiaceae, Philyra brasiliensis Klotzsch is distributed in northern Argentina, the southern half of Paraguay and midwest, southeast and northeast Brazil (Webster 2014Webster GL. 2014. Euphorbiaceae. In: Kubitzki K (ed.). The Families and Genera of Vascular Plants. Flowering plants. Eudicots. Malpighiales. Berlin, Springer. v. 11, p. 51-216.; Külkamp 2020b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.), always associated with seasonally dry tropical forests (Külkamp 2020bKülkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.).

Chiropetalum proved to be a monophyletic genus and is composed of 22 species (Külkamp et al. 2023a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.) distributed from Mexico to southern Argentina, with the highest species diversity in the central region of South America (Chile, southern Brazil, and Argentina) (Ingram 1980a Ingram J. 1980a. The generic limits of Argythamnia (Euphorbiaceae) defined. Gentes Herbarum 11: 427-436. , bIngram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468; Külkamp et al. 2020aKülkamp J, Iganci JRV, Cordeiro I. 2020a. Chiropetalum. In: Flora e Funga do Brasil . Rio de Janeiro, Jardim Botânico do Rio de Janeiro . http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB29160. 10 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... ; 2023aKülkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.). The genus has a large geographical disjunction, with two species restricted to Mexico and the other 18 south of the equator line (Ingram 1980bIngram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468; Pax & Hoffmann 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.; Radcliffe-Smith 2001Radcliffe-Smith A. 2001. Genera Euphorbiacearum. London, Royal Botanic Garden Kew.).

Taxonomic studies for the genera Argythamnia, Chiropetalum, and Philyra in South America are scarce, and Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) and Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.) treat the taxonomy of all then-known species of these genera. Only Ingram reviewed all species of Argythamnia (Ingram 1967Ingram J. 1967. A revisional study of Argythamnia subgenus Argythamnia (Euphorbiaceae). Gentes Herbarum 10: 1-38.) and Chiropetalum (Ingram 1980bIngram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468), otherwise no other study treats these genera in their entirety. Some regional studies have also treated the taxonomy for some genera, such as O’Donell & Lourteig (1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ) when present Caperonia, Chiropetalum and Ditaxis for Argentina, Ramírez-Amezcua & Steinmann (2013Ramírez-Amezcua Y, Steinmann VW. 2013. Revisión taxonómica de Argythamnia subgénero Ditaxis (Euphorbiaceae) en México. Botanical Sciences 91: 427-459.) treat Argythamnia subg. Ditaxis for Mexico and Külkamp et al. (2020b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.) present Argythamnia for the Brazilian Caatinga, Külkamp et al. (2023bKülkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ) present Argythamnia for Chacoan and Pampean provinces in South America. As part of the study of Adelieae and Ditaxeae systematics, here we present a taxonomic synopsis, with identification keys, taxonomic heading, nomenclature update, new species, diagnosis, distribution and ecology comments and notes for all South American species of Argythamnia, Chiropetalum and Philyra.

Materials and Methods

Fieldwork to observe and collect specimens was conducted from 2016 to 2022. Individuals were photographed, geographic coordinates were recorded, and samples were collected for morphological analysis: vouchers were deposited in the herbarium collection with your duplicates.

Physical and virtual specimens were consulted in the herbaria: A, ACOR, B, BA, BAA, BC, BM, BKL, BR, C, CAS, CEPEQ, CGMS, CM, COL, COR, CORD, CPAP, CTES, E, ECT, F, FLOR, G, GB, GH, GOET, HAL, HAS, HBG, HBR, HUEFS, ICN, K, LIL, LP, M, MA, MBM, MO, MOL, MPU, MVFA, MVJB, MVM, NY, P, PACA, PEL, R, RB, RSA, S, SGO, SI, SP, SPF, TUB, UC, UPCB, and US (acronyms follow Thiers 2023Thiers B. 2023. Index Herbariorum: A global directory of public herbaria and associated staff. New York, New York Botanical Garden’s, Virtual Herbarium. Available from: Available from: http://sweetgum.nybg.org/ih/. 02 Feb. 2023.
http://sweetgum.nybg.org/ih/.... , constant updating). All cited specimens have been seen at least online or physically by the first author.

Literature containing descriptions and protologues was consulted in libraries and online repositories, and the nomenclatural practice follows the International Code of Nomenclature for algae, fungi, and plants (ICN Turland et al. 2018Turland NJ, Wiersema JH, Barrie FR et al. 2018. International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code). Regnum Vegetabile 159. Glashütten, Koeltz Botanical Books.). The morphological terminology used in the descriptions was based on Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.), O’Donell & Lourteig (1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ), Ingram (1980a Ingram J. 1980a. The generic limits of Argythamnia (Euphorbiaceae) defined. Gentes Herbarum 11: 427-436. , bIngram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468), Webster (2014Webster GL. 2014. Euphorbiaceae. In: Kubitzki K (ed.). The Families and Genera of Vascular Plants. Flowering plants. Eudicots. Malpighiales. Berlin, Springer. v. 11, p. 51-216.), and Külkamp et al. (2023a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.). The concept and terminology of biogeographic provinces was based on Morrone (2006Morrone JJ. 2006. Biogeographic areas and transition zones of Latin America and the Caribbean Islands based on panbiogeographic and cladistic analyses of the entomofauna. Annual Review of Entomology 51: 467-494.; 2014Morrone JJ. 2014. Cladistic biogeography of the Neotropical region: Identifying the main events in the diversification of the terrestrial biota. Cladistics 30: 202-214.). The circumscription of the Seasonally Dry Tropical Forest biome followed Pennington et al. (2000Pennington RT, Prado DA, Pendry C. 2000. Neotropical seasonally dry forests and quaternary vegetation changes. Journal of Biogeography 27: 261-273.), Prado (2000Prado DE. 2000. Seasonally dry forests of Tropical South America: From forgotten ecosystems to a new phytogeographic unit. Edinburgh Journal of Botany 57: 437-461.) and Särkinen et al. (2011Särkinen T, Iganci JRV, Linares-Palomino R, Simon MF, Prado DE. 2011. Forgotten forests-issues and prospects in biome mapping using seasonally dry Tropical Forests as a case study. BioMed Central Ecology 11: 27.), and Brazilian biomes follow IBGE (2004IBGE - Instituto Brasileiro de Geografia e Estatística. 2004. Mapa de vegetação do Brasil. 3rd. edn. Rio de Janeiro, IBGE. 1 mapa: color. Escale 1:5.000.000.). Geographic distribution data were obtained from field collections, herbarium specimens viewed in person and online, and other databases such as GBIF (2023GBIF - The Global Biodiversity Information Facility. 2023. https://www.gbif.org/pt/occurrence. 12 Jan. 2023.
https://www.gbif.org/pt/occurrence.... ), REFLORA (2023REFLORA - Herbário Virtual. 2023. http://reflora.jbrj.gov.br/reflora/herbarioVirtual/. 15 January 2023.
http://reflora.jbrj.gov.br/reflora/herba... ), and speciesLink (2023SpeciesLink. 2023. SpeciesLink network and data providers. http://splink.cria.org.br/. 10 Oct. 2023.
http://splink.cria.org.br/.... ). For samples that did not have geographic coordinates, these were inferred from the locality (municipality, department or locality) described in label, and when the locality was not sufficiently detailed (only state, province or country level), the sample was not used in the analyses. The Extension of Occurrence (EOO) and Area of Occupancy (AOO) of the species were estimated with GeoCAT-Kew (Bachman et al. 2011Bachman S, Moat J, Hill AW, Torre J, Scott B. 2011. Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. ZooKeys 150: 117-126. doi: 10.3897/zookeys.150.2109
https://doi.org/10.3897/zookeys.150.2109... ). The distribution maps and Kernel Density Estimation maps were produced in QGIS (2017QGIS Development Team. 2017. QGIS Geographic Information System. V 2.18.2. Open Source Geospatial Foundation. http://qgis.osgeo.org/. 10 Oct. 2023.
http://qgis.osgeo.org/.... ). All distribution data were used in the Kernel Density Estimation maps, and for this analysis, pixels of 144 km² and a diameter of the analysis circle of 340 km were used.

Results and Discussions

Taxonomic Treatment

Key to Argythamnia, Chiropetalum and Philyra genera in South America with characters illustrated in Fig. 1

1. Shrub to treelet; thorn pairs present on the branches; leaves glabrous; floral nectaries absent Philyra

1’. Herb, subshrub or shrub; thorn pairs lacking; leaves pubescent; floral nectaries present 2

2. Staminate flower with lobed petals; stamens 3-6, arranged in one whorl Chiropetalum

2’. Staminate flower with unlobed petals; stamens 7-10, arranged in two whorls Argythamnia

Argythamnia P.Browne

Argythamnia P.Browne, The Civil and Natural History of Jamaica 3: 338. 1756.

Type: Argythamnia candicans Sw.

Description: Herbs to shrubs, annual or perennial, monoecious, rarely dioicous, acaulescent or not. Branches erect, decumbent or prostrate, covered by malpighiaceous and/or simple trichomes, lacking thorns. Stipules present, persistent or rarely caducous, ovate to lanceolate, pubescent rarely glabrous. Leaves simple, alternate, rosulate or not, petiolate, lanceolate, ovate, spatulate or elliptic, venation pinnate, margins serrate to entire, pubescent with malpighiaceous and/or simple trichomes. Racemes axillary, bi-unisexual, with proximal pistillate flowers and distal staminate flowers; flowers 1-bracteolate; bracteoles lanceolate to ovate, pubescent, rarely glabrous. Staminate flowers dichlamydeous; sepals 5(-4), valvate, linear to lanceolate, margin entire or serrate, pubescent or glabrous; petals 0-5, adnate to the staminal column, linear, lanceolate or elliptic, margin entire, pubescent or glabrous; stamens 4-10 rarely 12, free or arranged in a column with two whorls; staminodes 0-5 at the top of the staminal column, pubescent or glabrous; floral nectaries 4-5. Pistillate flowers dichlamydeous or monochlamydeous; sepals (4-)5(-6), valvate, linear, lanceolate, ovate or elliptic, pubescent rarely glabrous; petals 0-5, linear, lanceolate, oval, elliptic or rhomboid, pubescent or glabrous, unlobed, margins entire; floral nectaries 5, adnate to the receptacle at the base of the ovary, glabrous or ciliate; ovary pubescent; styles 3, entire, bifid or trifid, pubescent or glabrous. Capsule with three one-seeded loci. Seeds globose to ovoid, apiculate, surface smooth, undulate or reticulate, gray to black.

Of the 68 species recognized for Argythamnia, 22 are known from South America (Fig. 2 A -C), 20 of which are endemic to South America. The southernmost distribution of the genus is represented by A. malpighipila (Hicken) J.W.Ingram in northern Patagonia, Argentina (Fig. 2 B ), and farthest north by A. argothamnoides (Bertero ex Spreng.) J.W.Ingram, A. erubescens J.R.Johnst., and A. polygama (Jacq.) Kuntze, which occur in northern Colombia and Venezuela (Fig. 2 A ). The countries with the greatest species richness are Brazil, with 11 species, followed by Argentina with six (Fig. 2). Argythamnia species have a regionalized distribution pattern, presenting many regional endemics, with a small extent of occurrence. The highest concentration of records for Argythamnia is found in northeastern Brazil and northern South America, and the lowest in central South America (Fig. 3). The high number of records of Argythamnia in northeastern Brazil and northern South America is associated with many gatherings of A. desertorum Müll.Arg. and A. argothamnoides, respectively, whereas in central South America, the expressive number of collections is related with the species richness (Fig. 2 B ). The most widely distributed species in South America is A. montevidensis (Didr.) Müll.Arg., which occurs in the Chaco and Pampa provinces in central South America (Fig. 2 B ).

No species of Argythamnia are registered in western side of the southern half of the Andes, and this may be due to the diversification of the genus in South America after the uplift of the Andes or the extinction of the lineages with western distribution. Unlike Chiropetalum, Argythamnia has several species in the north and northeast of South America, and this distribution pattern can be explained by the occurrence of seasonally dry tropical forests, vegetation with the greater diversity of Argythamnia.

For Argythamnia, the Amazon region has proved to be a barrier that disconnects the eastern and western lineages of genus in South America (Figs. 2 and 3B). Apparently, it is an ancient barrier, as neither species occurs in eastern and western Amazonia simultaneously.

For the South American Argythamnia, we describe here a new species, designate 12 lectotypes and a new synonym.

Identification key to South American Argythamnia species

1. Acaulescent herbs or, if stem present, then prostrate; leaves rosulate 2

1’. Non-acaulescent herbs, subshrubs or shrubs, stems erect; leaves non rosulate (spaced along the branches) 3

2. Leaves linear to linear-elliptic; sepals of pistillate flowers 6, 9-11.4 mm long, lanceolate non-falcate 1. A. acaulis

2’. Leaves elliptic to obovate; sepals of pistillate flowers 5(6), 5.9-8.5 mm long, lanceolate falcate 21. A. sellowiana

3. Stems woody with prostrate branches; internodes 0.3-0.5 mm long; leaves 0.5-0.7 cm long 16. A. malpighipila

3’. Stems woody or herbaceous with erect branches; internodes 0.7-55 mm long; leaves 0.8-15.2 cm long 4

4. Inflorescences with 15-35 staminate flowers 20. A. salina

4’. Inflorescences with 1-14 staminate flowers 5

5. Staminate flowers with 8 stamens in two whorls (5+3) 17. A. montevidensis

5’. Staminate flowers with 9-10 stamens in two whorls (5+5 or 5+4) 6

6. Pedicel of the pistillate flower after anthesis 5-23 mm long 7

6’. Pedicel of the pistillate flower after anthesis 0.7-4.7 mm long 13

7. Leaf margin with 5-8 teeth (rarely absent) distributed in the distal half of the leaf 7. A. desertorum

7’. Leaf margin entire or with 9 or more teeth distributed from the base to the apex the leaf 8

8. Monoecious plants; 1 pistillate flower per inflorescence 9

8’. Dioecious plants; 1-4 pistillate flowers per pistillate inflorescence 11

9. Leaves obovate to obovate-lanceolate; sepals of the staminate flower 8-9 mm long; staminodes 5 13. A. katharinae

9’. Leaves elliptic to lanceolate; sepals of the staminate flower 1.5-5 mm long; staminodes 4 10

10. Pedicel scar not evident; leaf margin entire; sepals of pistillate flowers 9-12 mm long 22. A. simoniana

10’. Pedicel scar evident; leaf margin serrate; sepals of pistillate flowers 5-6.4 mm long 2. A. acutangula

11. Petals of the pistillate flower 4-5.5 mm long, linear 8. A. dioica

11’. Petals of the pistillate flower 6-10 mm long, lanceolate, elliptic or oblanceolate 12

12. Stipules ca. 3 mm long; leaves sparsely pubescent; style + stigma ca. 1.5 mm long 18. A. polygama

12’. Stipules 1-2.5 mm long; leaves densely pubescent; style + stigma ca. 3 mm long 14. A. macrantha

13. Leaves spatulate to obovate 2. A. cuneifolia

13’. Leaves lanceolate, elliptic or ovate 14

14. Leaf margin entire 15

14’. Leaf margin serrate or serrulate 16

15. Erect herbs; 1 pistillate flower per inflorescence; petals of the pistillate flower longer than the sepals; styles entire 12. A. jablonszkyana

15.’ Shrubs or subshrubs; 2-3 pistillate flowers per inflorescence; petals of the pistillate flower shorter than the sepals; styles bifid 15. A. malpighiacea

16. Leaf margin entire to 11 teeth 17

16’. Leaf margin bearing 12 or more teeth 19

17. Sepals of the staminate flowers 3.9-4.1 mm long, pubescent on both surfaces; staminal column ca. 3.5 mm long 9. A. erubescens

17’. Sepals of the staminate flowers shorter than 3.7 mm long, pubescent on the abaxial surface only; staminal column ca. 2 mm long 18

18. Leaves elliptic; petiole 1-1.5 mm long 5. A. breviramea

18’. Leaves lanceolate; petiole ca. 10 mm long 11. A. illimaniensis

19. Petals of the pistillate flower ca. 0.3 mm long; sepals of the staminate flowers 1.5-2.8 mm long 19. A. purpurascens

19’. Petals of the pistillate flower 1.5-3 mm long; sepals of the staminate flowers 3-3.8 mm long 20

20. Sepals of pistillate flowers serrate; staminal column 1.2-1.5 mm long 10. A. grazielae

20’. Sepals of pistillate flowers entire; staminal column 1.9-3.1 mm long 21

21. Leaf margin with 35 or more teeth; inflorescence 9-12 mm long; staminate flowers 9-14 per inflorescence 3. A. alcalina sp. nov.

21’. Leaf margin with 14-22 teeth; inflorescence 4-8 mm long; staminate flowers 4-8 per inflorescence 4. A. argothamnoides

1. Argythamnia acaulis (Herter) J.W.Ingram, Bulletin of the Torrey Botanical Club 84: 422. 1958. Ditaxis acaulis Herter, Anales del Museo Nacional de Montevideo 1: 79. 1911. Paxia acaulis (Herter) Herter, Estud. Bot. Reg. Uruguay 4: 80. 1931. Paxiuscula acaulis (Herter) Herter, Revista Sudamer. Bot. 6: 93. 1939. Type: URUGUAY: Vale Eden, s.d., J. Arechavaleta 15 ex part (destroyed). Neotype (designated by Külkamp et al. 2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ): URUGUAY. ARTIGAS: Cuarein, Entre peñascos. Sep (no year), J. Arechavaleta 15 (MVM [MVM5191])!.

Description: Herbs, monoecious, 5-10 cm tall, acaulescent and prostate, with woody tubers; internodes 0.1-0.4 mm long; leaves rosulate, blade 2-7 cm long, linear to linear-elliptic, margin entire; racemes 5-7 mm long, 1 basal pistillate flower, 3-5 distal staminate flowers; stamens 8, staminodes absent; pistillate flowers with 6 sepals, 9-11.4 mm long, lanceolate, margin entire, petals 5, styles bifid.

Distribution and habitat: Argythamnia acaulis is restricted to southern Brazil, in the state of Rio Grande do Sul, and northern Uruguay (Fig. 2 C ). The species is endemic to the grassland of the Pampa Province and is always associated with grazed and stony soils.

Flowering and fruiting: Flowers and fruits from September to January.

Notes: Despite having the same collection number as the original material (J. Arechavaleta 15), the neotype designated for A. acaulis has a different collection locality on the label. This species is morphologically similar to A. sellowiana (Pax & K.Hoffm.) J.W.Ingram, and as a consequence, many specimens are mistakenly identified, giving the impression that A. acaulis is a widely distributed species.

Selected specimens examined: BRAZIL. RIO GRANDE DO SUL: Santana do Livramento. Vigia, 14 Jan 1941, (fl. fr.), B. Rambo11350 (SP). URUGUAY. RIVERA: Barren hill-top with flat outcrops near Rivera, 07 Dec 1943, (fl. fr.), H.H. Bartlett 21079 (US); Cerros, 20 Jan 1944, (fl. fr.), C.D. Legrand 3565 (MVFA, MVM). ARTIGAS: Cuareim, Sep, (fl. fr.), J. Arechavaleta 15a (MVM5191a). TACUAREMBÓ: Tambores, (fl. fr.), C.D. Legrand 2640 (MVM); Tambores. Vale Edén, (fl. fr.), A.E. Paz 792 (MVM).

2. Argythamnia acutangula Croizat, Ciencia (Mexico) 6: 353. 1946. Type: COLOMBIA. DEL VALLE: Cordillera Occidental, vertiente occidental, Lobo Guerrero, 610-650 m, 9-10 Sep 1944, J. Cuatrecasas 17808 (holotype: GH [GH00045755]!, isotypes: A [A00045756]!, BC [BC638422]!, COL [COL000002061]!, F [F0055883F]!, P [P00634984]!, U [U0001862]!, US [US00109826]!.

Description: Subshrub to shrub, monoecious, without woody tubers; stems erect, internodes 1-20 mm long; pedicel scar evident, leaves not rosulate, blade 2-4.1 cm long, elliptic, margin serrate, 10-16 teeth; racemes 2-3 mm long, 1 pistillate flower basal, 3-5 staminate flowers distally; staminate flower with sepals ca. 3 mm long, stamens 10, staminodes 4, pubescent; pistillate flowers with pedicel 5.5-8 mm long, sepals 5, 5-6.4 mm long, margin entire, petals 5, 4-5 mm long, linear, styles bifid.

Distribution and habitat: Argythamnia acutangula is endemic to Colombia (Fig. 2 B ) and known from only three localities. The species occurs in seasonally dry tropical forest of the Cauca and Magdalena Provinces.

Flowering and fruiting: Flowers and fruits from August to December.

Notes: Rare species, known from three herbarium records, the type and another two records determined as cf. at COL herbarium.

Selected specimens examined: COLOMBIA. TOLIMA: Mendez, finca Bremen, 300 m, 20 Nov 1995Lima HC. 1995. Leguminosas da Florae Fluminensis - J.M. da C. Vellozo. Lista Atualizada das espécies Arbóreas. Acta Botanica Brasilica 9: 123-146., (fl. fr.), H. Mendonza 9 (COL). VALLE DE CAUCA: D’agua, Lobo Guerrero, 800 m, 1 Aug 2003, (fl.), W.G. Vargas et E. Méndez 11821 (ICESI).

3. Argythamnia alcalina Külkamp, sp. nov. (Fig. 4)Type: BRAZIL. MINAS GERAIS: Santo Hipólito, 6 km após Santo Hipólito sentido Conselheiro Mata, margem da estrada, próximo a um bueiro, 5 metros no interior da mata, 18°17’23.2’’ S 44°11’15.1’’ W, 540 m, 18 June 2019, (fl. fr.), J. Külkamp et al. 914 (holotype: RB [RB788140]!, isotypes: CGMS!, ICN!, SP!, SPF!, US!)

Diagnosis: Species similar to A. grazielae due to the elongated staminate flowers buds; seeds apiculate and reticulate surface, leaf margin with more than 20 teeth. Argythamnia alcalina can be differentiated by having racemes 4-7 mm long (vs. 9-12 mm long), 9-15 staminate flowers per inflorescence (vs. 7-10 flowers), a staminal column 2.9-3.1 mm long (vs. 1.2-1.5 mm long), absence of staminodes in staminate flower (vs. 4 apical staminodes), and seeds 1.9-2.4 mm long (vs. 3.3-3.5 mm long).

Description: Subshrub to shrub 0.5-2 m tall, monoecious; stems erect, internodes 3-34 mm long.; stipules 1.2-1.9 × 0.2-0.35 mm, persistent, lanceolate, with malpighiaceous and simple trichomes on both surfaces; leaves not rosulate; petiole 3-7 mm long, with malpighiaceous trichomes; blade 3.8-15.2 × 1.3-5.2 cm, elliptic, base acute to cuneate, apex acute to acuminate, acrodromous venation, evident on both surfaces, secondary veins 4-6 pairs, margin serrate to serrulate with 35 or more teeth; racemes 9-12 mm long, axillary, bisexual, 1-2 pistillate flowers proximally, 9-14 staminate flowers distally; bracts 1.2-1.5 × 1-1.2 mm, ovate, concave, with malpighiaceous trichomes on both surfaces; staminate flowers: bud elongated, pedicels 1-1.3 mm long, sepals 5, 3.4-3.8 × 0.8-1.1 mm long, linear, margin entire, pubescent only on the abaxial surface, petals 5, 2.8-3 × 0.9-1.1 mm, elliptic, adnate to the staminal column, yellowish, margin entire, pubescent only on the veins of the abaxial surface, staminal column 2.9-3.1 mm long, free portion of the filaments 0.3-0.4 mm long, stamens 10 arranged in two whorls (5+5), pubescent at the top of the staminal column, staminodes absent, nectaries 5, ovate apiculate, base adnate to the staminal column; pistillate flowers: pedicels 1.3-2 mm long, sepals 5, 5-6.8 × 3.5-4.9 mm, ovate to lanceolate, apex acute, margin entire, pubescent on both surfaces; petals 5, 1.8-2.1 × 0.8-1 mm, linear to elliptic, base cuneate, apex acute, yellowish, pubescent on both surfaces, margin ciliate; nectaries 5, ligulate, adnate to the receptacle, alternate to the petals, ciliate; ovary pubescent, styles 1.9-2 mm long, bifid, free portion ca. 0.9 mm long, pubescent at the apex, stigmas flattened; capsule 6-9 × 4.5-6 mm, splitting at maturity into 3, 1-seeded cocci, densely pubescent; seeds 3.3-3.5 × 2.9-3 mm, oval, rounded to truncate at the base, acute apex, reticulate surface, gray to black.

Etymology: The specific epithet refers to the environment in which the species occur, which has limestone soils.

Distribution and habitat: Argythamnia alcalina is endemic to Brazil, and all of its records are from the states of Minas Gerais and Goiás (Fig. 2C). Four localities are known for the species, all belonging to seasonally dry tropical forest, as defined by Pennington et al. (2000Pennington RT, Prado DA, Pendry C. 2000. Neotropical seasonally dry forests and quaternary vegetation changes. Journal of Biogeography 27: 261-273.), Prado (2000Prado DE. 2000. Seasonally dry forests of Tropical South America: From forgotten ecosystems to a new phytogeographic unit. Edinburgh Journal of Botany 57: 437-461.) and Särkinen et al. (2011Särkinen T, Iganci JRV, Linares-Palomino R, Simon MF, Prado DE. 2011. Forgotten forests-issues and prospects in biome mapping using seasonally dry Tropical Forests as a case study. BioMed Central Ecology 11: 27.). According to the classification by Morrone (2014Morrone JJ. 2014. Cladistic biogeography of the Neotropical region: Identifying the main events in the diversification of the terrestrial biota. Cladistics 30: 202-214.) and IBGE (2004IBGE - Instituto Brasileiro de Geografia e Estatística. 2004. Mapa de vegetação do Brasil. 3rd. edn. Rio de Janeiro, IBGE. 1 mapa: color. Escale 1:5.000.000.), this region is part of the Cerrado biome. However, based on the classification of vegetation for Brazil it is denominated “Floresta Estacional Decidual” (Veloso et al. 1991Veloso HP, Rangel Filho ALR, Lima JCA. 1991. Classificação da vegetação brasileira, adaptada a um sistema universal. Rio de Janeiro, IBGE .), “Floresta Estacional Decidual de Encosta”, “Mata Seca de Calcário” or “Mata Calcária” (Fig. 4 A ) (Nascimento et al. 2004Nascimento ART, Felfili JM, Meirelles EM. 2004. Florística e estrutura da comunidade arbórea de um remanescente de Floresta Estacional Decidual de encosta, Monte Alegre, GO, Brasil. Acta Botanica Brasílica 18: 659-656.). The forests in these areas have above 50% of species with deciduous leaves in the in the dry season (April to September) and the most abundant taxa are from the Anacardiaceae, Bignoniaceae, Leguminosae, and Malvaceae families (Nascimento et al. 2004Nascimento ART, Felfili JM, Meirelles EM. 2004. Florística e estrutura da comunidade arbórea de um remanescente de Floresta Estacional Decidual de encosta, Monte Alegre, GO, Brasil. Acta Botanica Brasílica 18: 659-656.). The type locality is extremely degraded, in an initial succession stage, as the forest vegetation is composed of sprouts of native species, and currently the forest canopy does not exceed 10 meters in height. The area presents limestone soils, reddish in color, with exposed rocks in some places (Fig. 4 B -C). The other three collection sites of A. alcalina also have limestone soils and seasonal forest. Argythamnia alcalina grows in dense and sporadic groups inside the forest and less often along the edges.

Flowering and fruiting: Flowering and fruiting from January-June, a period that partially corresponds to the rainy season in the region, which occurs from October/November to March.

Conservation status: Only seven collections of the new species are known from four localities. However, only the population of Santo Hipólito is known by the author. In this site, approximately 50 adult individuals and some juveniles were observed. Specimens from other sites do not present abundance information on labels. The species has an AOO of 20 km² and EOO of 29,197 km². The three collections J. Külkamp et al. 912, 913 and 914 were considered a single point for the AOO and EOO estimation, as they were collected in the same local at distances of less than 10 meters from each other. Using the IUCN (2013IUCN. 2013. Guidelines for using the IUCN Red List Categories and Criteria. Version 10. Prepared by the Standards and Petitions Subcommittee. https://www.iucnredlist.org/resources/redlistguidelines/. 20 Jan. 2023.
https://www.iucnredlist.org/resources/re... ) guidance, the species was classified as EN B2ab(i,ii,iii,v). The most prevalent threats to populations are the fragmentation of habitat by the suppression of vegetation by anthropic actions.

Notes: In addition to presenting similar morphology, A. alcalina is phylogenetically close to A. grazielae (endemic to the Caatinga) as can be seen in the phylogenetic reconstruction by Külkamp et al. (2023 a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.), where these emerges as sister species. Argythamnia alcalina also emerges in a clade with the other species endemic of the Caatinga (Külkamp et al. 2020bKülkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.), reinforcing the floristic similarity between the Caatinga and the Cerrado, both formations that have seasonally dry tropical forest in their composition.

Argythamnia alcalina is a rare species and only a few specimens have been gathered. According to the Minas Gerais state inventories of Meguro et al. (2007Meguro M, Pirani JR, Mello-Silva R, Cordeiro I. 2007. Composição florística e estrutura das florestas estacionais decíduas sobre calcário a oeste da Cadeia do Espinhaço, Minas Gerais, Brasil. Boletim de Botânica da Universidade de São Paulo 25: 147-171.), where five seasonal forests on limestone soil areas were studied, the only site where the species was registered is Santo Hipólito. Seasonally dry tropical forests have been shown to be an important formation for the occurrence of Argythamnia, and seasonal forests associated with limestone soil have contributed to micro-endemisms, such as A. purpurascens in Corumbá in Mato Grosso do Sul. Endemism associated with dry forests and calcareous soils is not new in the subfamily Acalyphoideae, and is a well-known case is Leucocroton alliance, with distribution in the Antilles (Jestrow et al. 2012Jestrow B, Amaro JG, Francisco-Ortega J. 2012. Islands within islands: a molecular phylogenetic study of the Leucocroton alliance (Euphorbiaceae) across the Carribean Islands and within the serpentinite archipelago of Cuba. Journal of Biogeography 39: 452-464. ).

Paratypes: BRAZIL. GOIÁS: São Domingos, ca. 50 km de São Domingos, Gruta Terra Ronca, 13°44’2”S 46°21’25”W, 580-700 m, 24 February 2003, (fl. fr.), F. França 4666 (HUEFS). MINAS GERAIS: Itacarambi, nas redondezas do Parque Nacional Cavernas do Peruaçu, 15°14’23.5’’ S 44°13’31.1’’ W, 17 December 2018, (fl.), J.F. Carrión et al. 1905 (HUEFS); Santo Hipólito, Estrada Corinto-Conselheiro Mata, a 6 km E de Santo Hipólito, 18°17’ S 44°13’W, 550 m, 3 April 1996, (fl. fr.), J.R. Pirani et al. 3729 (HUEFS, MBM, NY, SP, SPF); Santo Hipólito, 6 km após Santo Hipólito sentido Conselheiro Mata, margem da estrada, próximo a um bueiro, 5 metros no interior da mata, 18°17’23.2”S 44°11’15.1”W, 540 m, 18 June 2019, (fl. fr.), J. Külkamp et al. 912 (BHCB, RB, SP, US); (fl. fr.), J. Külkamp et al. 913 (HUEFS, K, MEXU, NY, RB, SPF); Varzelandia, Barreirinho, 7 February 1985, (fl.), J.G. Silva & M. Menezes 1136 (IAB, R).

4. Argythamnia argothamnoides (Bertero ex Spreng.) J.W.Ingram, Bulletin of the Torrey Botanical Club 80(5): 423. 1953. Croton argothamnoides Bertero ex Spreng., Systema Vegetabilium, 3: 872. 1826. Argythamnia argothamnoides (Bertero ex Spreng.) Radcl.-Sm. & Govaerts, Kew Bulletin 52(2): 479. 1997. Type: COLOMBIA. MAGDALENA: Santa Martha, 1816-1821, C.L.G. Bertero s.n. (lectotype designated here: TO 6480! [specimen has a label written “HERB. BALBIS” in the lower right corner above the label with the data collection. The specimen is composed of a single branch of the plant]). Syntype remaining: COLOMBIA. MAGDALENA: Santa Martha, no date, C.L.G. Bertero 1579 (TO 6480! [this specimen is mounted with another specimen, number 2767. However, the collector’s name is illegible]).

= Aphora blodgetti Torr. ex Chapm., Flora of the Southern United States 408-409. 1860. Ditaxis blodgettii (Torr. ex Chapm.) Pax, Die Natürlichen Pflanzenfamilien 3(5): 45. 1890. Argythamnia blodgettii (Torr. ex Chapm.) Chapm., Flora of the Southern United States (ed. 3) 3: 431. 1897. Type: UNITED STATES. FLORIDA: Key West, J.L. Blodgett s.n. (holotype: NY [NY00246211]!).

= Argythamnia savanillensis Kuntze, Revisio Generum Plantarum 2: 593-594. 1891. Type: COLOMBIA. Savanilla. 31 May 1874, O. Kuntze 1805 (lectotype designated here: NY [NY00246261!], isolectotype: K [K000600280]!).

= Argythamnia fendleri Müll.Arg., Linnaea 34(2): 145-146. 1865. Ditaxis fendleri (Müll.Arg.) Pax & K.Hoffm., Das Pflanzenreich IV.147.vi (Heft 57), 61. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Type: VENEZUELA. MARACAYBO: K. Moritz 1325 (lectotype designated here: HBG [HBG516357]!, isolectotype: HBG [HBG516404]!).

= Argythamnia rubricaulis (Pax & K.Hoffm.) Croizat, Ciencia (Mexico) 6(10-12): 353. 1946. Ditaxis rubricaulis Pax & K.Hoffm., Notizblatt des Botanischen Gartens und Museums zu Berlin-Dahlem 10(94): 383-384. 1928. Type: VENEZUELA. Cabo blanco, dry ravine, 20 Feb 1922, H. Pittier 10192 (lectotype designated here: GH [GH00047619]!, isolectotype: K [K000600278]!, US [US00109823]!).

Description: Subshrub to shrub monoiceous, without woody tubers; stems erect, internodes 10-22 mm long; leaves not rosulate, blade 2-5.5 cm long, elliptic to obovate, margin serrate, 14-22 teeth; racemes 4-8 mm long, 1 pistillate flower basal, 4-8 staminate flowers distally, with sepals ca. 3 mm long, staminal column ca. 2.2 mm long, stamens 9-10, staminodes 3, glabrous; pistillate flowers with pedicel 1-3.2 mm long, 5 sepals, margin entire, petals 5, 1.8-3 mm long, styles bifid.

Distribution and habitat: Argythamnia argothamnoides is distributed in the Antilles, the state of Florida in the United States, and in South America, in northern Colombia and Venezuela (Fig. 2B), in Guajira and Venezuelan provinces. It occurs mainly in seasonally dry open vegetation and coastal regions with sandy soil.

Flowering and fruiting: Flowers and fruits all year round.

Notes: Argythamnia argothamnoides has been widely collected, and due to nomenclatural problems and morphological variation, many names have been proposed for this taxon. Carlo Luigi Giuseppe Bertero traveled to the Antilles and Colombia between 1816-1821 and made many collections (Stafleu & Mennega 1992Stafleu FA, Mennega EA. 1992. Taxonomic Literature: A selective guide to botanical publications and collections with dates, commentaries and types. suppl. 1. Königstein, Koeltz Scientific Books.; Delprete et al. 2002Delprete PG, Forneris G, Pistarino A. 2002. Carlo Bertero (1789-1831) in the New World. SIDA, Contributions to Botany 20: 621-644.). During the trip, he also described in his field diary the plant’s morphology and local names, as well as uses and pharmacological properties (Delprete et al. 2002Delprete PG, Forneris G, Pistarino A. 2002. Carlo Bertero (1789-1831) in the New World. SIDA, Contributions to Botany 20: 621-644.). The collections were sent to Giovanni Battista Balbis and Luige Colla in Turin, Italy (Delprete et al. 2002Delprete PG, Forneris G, Pistarino A. 2002. Carlo Bertero (1789-1831) in the New World. SIDA, Contributions to Botany 20: 621-644.). Balbis received most of the collections from Bertero, and these were studied in part by Curt Sprengel and later distributed to other European herbaria (Delprete et al. 2002Delprete PG, Forneris G, Pistarino A. 2002. Carlo Bertero (1789-1831) in the New World. SIDA, Contributions to Botany 20: 621-644.).

Based on the specimens collected by Bertero in the Antilles and Colombia, Sprengel (1826Sprengel CPJ. 1826. Systema Vegetabilium. Göttingen, German . v. 16, 3, p. 1-936.) described Croton argothamnoides, mentioning in the protologue Magdalena as type locality. Two specimens collected by Bertero in the town of Santa Marta (city of Magdalena in Colombia) were found in the TO herbarium with the same registration number (TO 6480). One of them, Bertero s.n. has the label “HERB. BALBIS”, while the other, Bertero 1579 does not have the label “HERB. BALBIS”. We consider the two as different collections. Sprengel probably analyzed these two specimens for the description, and for this reason, we designate the specimen Bertero s.n. (HERB. BALBIS [TO 6480]), as the lectotype of C. argothamnoides, and the specimen Bertero 1579 remains as a syntype. It is worth mentioning that on the same sheet as Bertero 1579 there is another specimen with the number 2767. Despite being a specimen of A. argothamnoides, nothing indicates that this material is part of Bertero’s gathering.

For A. blodgettii, we consider the specimen J.L. Blodgett s.n. (NY00246211) as the holotype, because it is the only specimen found and was deposited in Torrey’s private collection, author of the species.

Argythamnia savanillensis was described based on syntypes (without the indication of a specific specimen as type), so we designate here the specimen O. Kuntze 1805 (NY00246261) as this name’s lectotype.

Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) described Ditaxis fendleri, citing Croton argothamnoides as a synonym. This name is valid since it is based on a description and different specimens. In the protologue, the author refers to seven collections (syntypes) of A. fendleri. We treat A. fendleri as a synonym, and designate here the specimen K. Moritz 1325 (HBG516357) as this name’s lectotype. The remaining specimens we treat as syntypes.

Pax & Hoffmann (1928Pax F, Hoffmann K. 1928. Ditaxis rubricaulis. Notizblatt des Botanischen Gartens und Museums zu Berlin-Dahlem, 10: 1-384.) described D. rubricaulis based on the collection Pittier 10192, without mentioning a specimen as a type. So, here we designate Pittier 10192 (GH00047619) as lectotype of the name. We also consider this taxon as a synonym for A. argothamnoides, agreeing with previous authors (Ulloa et al. 2018Ulloa UC, Acevedo-Rodríguez P, Beck SG et al. 2018. Vascular Plants of the Americas. St. Louis, Botanical Information System at the Missouri Botanical Garden. http://www.tropicos.org/Project/VPA. 27 Apr 2023.
http://www.tropicos.org/Project/VPA.... ).

Selected specimens examined: COLOMBIA. LA GUAJIRA: along the road, 30 Sep 1921, (fl. fr.), H. Pittier 9847 (US). MAGDALENA: Santa Marta, Gaira, Aug 1898-1901, (fl. fr.), H. Smith 1218 (US). VENEZUELA. MARACAIBO: 1893, (fl.), Mocquerys 803 (COL). MERIDA: Cardonales, 600-700 m, 31 Aug 1966, (fl. fr.), J.A. Steyermark et M. Rabe 97005 (US). NOVA ESPARTA: Pampatar, Dec 1951, (fl. fr.), H. Gines 3116 (US). PUERTO DE HIERRO: Ensenada del Fraile, 21 Aug 1961, (fl. fr.), L. Aristeguieta 4759 (US).

5. Argythamnia breviramea Müll.Arg., Linnaea 34: 146. 1865. Ditaxis breviramea (Müll.Arg.) Pax & K.Hoffm. Pflanzenr. IV.147.vi (Heft 57), 65. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Type: BOLIVIA. LACAREJA: vicinity Quiabaya, inter Motoata et Milguaya, 2550 m, Mar-Apr 1861, G. Mandon 1082 (lectotype designated by Külkamp et al. (2023Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... b): G [G00313540]!, isolectotypes: P [P00634952]!, F [F873414]!, K [K000600279]!, P [P00634953]!, S [S07-12642]!).

Description: Shrub, dioecious or rare monoecious, without woody tubers; stems erect, internodes 1.2-21 mm long; leaves not rosulate, petiole 1-1.5 mm long, blade 0.9-3.2 cm long, elliptic, margin serrate rarely entire, 5-10 teeth rarely absent; racemes ca. 3 mm long, 1 pistillate flower, 2 staminate flowers, with sepals ca. 3.5 mm long, pubescent on abaxial surface, staminal column ca. 2 mm long, stamens 10, staminodes 5, pubescent; pistillate flowers with pedicel ca. 1 mm long, sepals 5, margin entire, petals 5, styles bifid.

Distribution and habitat: Argythamnia breviramea is distributed in northern Argentina, northern Paraguay, and southern Bolivia (Fig. 2 C ). It is restricted to arid regions in shrubby vegetation, between 350-2500 meters elevation, in the Chaco and Monte provinces.

Flowering and fruiting: Argythamnia breviramea has been collected fertile throughout the year.

Notes: Few cases of dioecy have been reported for Argythamnia. Most species are monoecious, such as A. malpighiacea Üle and A. desertorum (Külkamp et al. 2020Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.a). Based on two specimens cited from Rio Negro, Argentina, O’Donell and Lourteig (1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ) characterized A. breviramea as monoecious and reported the rare presence of pistillate and staminate flowers in the same specimen.

Selected specimens examined: ARGENTINA. CORDOBA: Ischilín. Entre Las Lajas y Masa, a +8 Km antes de Masa, 2 May 1958, (fl.), A.T. Hunziker 13651 (CORD, MBM, RB, SI); FORMOSA: Pozo de Maza. 135 km al N de La Cañada del Rosillo, 16 Jun 1972, (fl.), R. Burkart 31 (SI); LA RIOJA: General Belgrano. Sierra de los Llanos (Falda 0), Entre Olta y el dique homónimo, 19 Feb 1959, (fl. fr.), A.T. Hunziker 13913 (CORD, SI); SALTA: Guachipas. La Viña, RN68, Em vale próximo a rodovia, 25°50’45.5”S, 65°42’09.0”W, 26 Oct 2018, J. Külkamp 563 (RB); SANTIAGO DEL ESTERO: Pellegrini. Cerro de Remate, 2 Apr 1989, (fl.), T.M. Pedersen 15364 (MBM, SI); BOLIVIA. Región Andina. Cataña. 2450 m, Nov 1911, (fl. fr.), B. Otto 3308 (NY, US); SANTA CRUZ: Curuyuqui. 50 km SE of Santa Cruz on Rio Parapeti, upland chaco, 18°45’56”S, 62°13’59”W, 350 m, 25 Oct 1991, A. Gentry, R. Foster et M. Peña 75208 (NY). PARAGUAY. ALTO PARAGUAY: Mayor Pablo Lagerenza. 6 Apr 1978, (fl. fr.), A. Schinini et E. Bordas 14996 (SI). NUEVA ASUNCIÓN: Circa de Estancia Capagro, 586 km de Asuncion, 7 Mar 1980, (fl), Bernardi 20207 (NY, MO).

6. Argythamnia cuneifolia (Pax & K.Hoffm.) J.W.Ingram, Bulletin of the Torrey Botanical Club 84: 422. 1958. Ditaxis cuneifolia Pax & K.Hoffm., Pflanzenr. 4. 147(6), 57, 180. 1924. Type: BRAZIL. ESPÍRITO SANTO: Rio Mutum, Feb 1917, P. Luetzelburg 7181 (holotype: M [M0244038]!).

Description: Herb monoecious, without woody tubers; stems erect, internodes longer than ca. 10 mm; leaves not rosulate, blade 9-13 cm long, spatulate to obovate, margin dentate; racemes ca. 60 mm long; 1 pistillate flower; staminate flowers 4-7, stamens 10; staminodes non seen; pistillate flowers with a pedicel ca. 3.5 mm long, sepals 5, margin entire, petals 5, styles bifid.

Distribution and habitat: Argythamnia cuneifolia is endemic to the state of Espírito Santo, Brazil (Fig. 2 B ) and is restricted to the Seasonally Dry Tropical Forest biome in the Atlantic province.

Flowering and fruiting: The only known collection was collected in February.

Notes: Argythamnia cuneifolia is one of the rarest species of Argythamnia, known only from the type collection, which only consists of the holotype deposited in the herbarium M, the destination of Luetzelburg collections (Stafleu & Cowan 1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.). The species has not been encountered for more than 105 years, and it is listed as a possibly extinct species on the list of threatened flora and fauna of Espírito Santo (Fraga et al. 2019Fraga CN, Peixoto AL, Leite YLR et al. 2019. Lista da fauna e flora ameaçadas de extinção no estado do Espírito Santo. In: Fraga CN, Formigoni MH, Chaves FG (eds.). Fauna e flora ameaçadas de extinção no estado do Espírito Santo. Santa Teresa, Instituto Nacional da Mata Atlântica. p. 343-397.). Expeditions to the region were not successful in finding the species, and the area has been heavily impacted with only a few fragments of native vegetation remaining. New explorations will be conducted to search for the species.

7. Argythamnia desertorum Müll.Arg., Flora Brasiliensis 11(2): 310. 1874. Ditaxis desertorum (Müll.Arg.) Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 62. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Type: BRAZIL. BAHIA: In silvis Catingas inter Feira de Santana, et Queimadas desertis, no date, C.F.P. Martius s.n. (lectotype designated by Külkamp et al. 2020 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.: M [M0244039]!, isolectotypes: G [G00434812]!, M [M0244040]!).

=Argythamnia gardneri Müll.Arg. Flora Brasiliensis 11(2): 310. 1874. Ditaxis gardneri (Müll.Arg.) Pax & Hoffmann Pflanzenr. IV.147.vi (Heft 57), 61. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Type: BRAZIL. PIAUI: 1839, G. Gardner 2444 (lectotype designated by Külkamp et al. 2020 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.: K [K000600284]!; isolectotypes G [G00434850]!, G [G00434851]!, K [K000600285]!, L!, W!).

Description: Shrub monoecious, without woody tubers; stems erect, internodes 3-40 mm long; leaves not rosulate, blade 1.5-9 cm long, obovate, elliptic or lanceolate, upper half margin serrate to entire, 5-8 teeth, rarely absent; racemes 10-40 mm long, 1 basal pistillate flower, 3-6 distal staminate flowers, stamens 10, staminodes 5, pubescent; pistillate flower pedicel 6-15 mm long, sepals 5, margin entire, petals 5, styles bifid.

Distribution and habitat: The species is endemic to northeastern Brazil (Fig. 2 B ), where it is widely distributed in Caatinga province associated with arboreal and shrubby vegetation. The Caatinga is one of the largest provinces that make up the Seasonally Dry Tropical Forest biome, further reinforcing the pattern of distribution of the genus in these environments and their importance for the conservation of the genus.

Flowering and fruiting: Argythamnia desertorum has been collected fertile throughout the year. A detailed discussion about this species is presented in Külkamp et al. (2020 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.).

Selected specimens examined: BRAZIL. ALAGOAS: Água Branca, 9°17’57”S, 37°55’44”W, 31 August 2013, M.C.S. Mota 12077 (RB). BAHIA: Bom Jesus da Lapa, 13°15’00”S 43°25’00”W, 11 April 2005, (fl. fr.), J.G.C. Sobrinho 504 (HUEFS); Iaçu, 12°48’24”S 40°07’23”W, 14 December 2018, (fl. fr.), J. Külkamp et al. 631 (RB). CEARÁ: Baturité, 4°17’32”S 38°54’58”W, 13 July 1908, (fr.), A. Ducke 1238 (RB). MINAS GERAIS: Monte Azul, 15°14’06”S 42°54’48”W, 22 April 2006, D.S. Carneiro-Torres 725 (HUEFS). PARAÍBA: Cacimba de Dentro, 6°40’60”S 35°44’59”W, 13 April 2002, (fl.), M.R. Barbosa 2375 (HUEFS); PERNAMBUCO: Arcoverde, 8°25’08”S 37°03’14”W, 29 March 2006, (fl. fr.), D. Costa et M.B. Silva 2137 (HUEFS). PIAUÍ: São José do Piauí, 6°52’18”S 41°28’31”W, 12 February 2002, (fl. fr.), M.R.A. Mendes 541 (EAC). RIO GRANDE DO NORTE: Areia Branca, 4°57’16”S 36°56’39”W, 4 September 2016, (fl. fr.), E.O. Moura 602 (UFRN). SERGIPE: Frei Paulo, 10°32’58”S 37°32’03”W, 11 November 1986, (fl. fr.), G. Viana 1647 (ASE).

8. Argythamnia dioica (Kunth) Müll.Arg., Linnaea 34: 145. 1865. Ditaxis dioica Kunth, Nova Genera et Species Plantarum, 7: 130, pl. 639. 1825. Type: PERU. JAEN: Jaen de Bracamoros, Ripam fluminis Amazonum, M.A. Bompland & A. Humboldt 3604 (lectotype designated here: P [P00634954]!, isolectotypes: P [P00634955]!, G [G00434811]!.

Description: Subshrub to shrub dioecious, without woody tubers; stems erect, internodes 1-10 mm long; leaves not rosulate, blade 0.8-7.3 cm long, elliptic, margin serrate, 12-25 teeth; racemes 1-8 mm long, 1 pistillate flower, 3-8 staminate flowers, stamens 10, staminodes 4, pubescent; pistillate flowers with a pedicel 6-8 mm long, sepals 5, margin entire, petals 5, 4-5.5 mm long, linear, styles bifid.

Distribution and habitat: The species is endemic to the Yunga province in northern Peru (Fig. 2 A ). The environment in which the species occurs is a shrubby vegetation on dry and stony slopes.

Flowering and fruiting: Argythamnia dioica has been collected fertile from November to May.

Notes: Carl Sigismund Kunth studied and described many of the species collected by Humboldt and Bonpland during the expedition to South America; most of the collections of the expedition were sent to Kunth in Paris, to be part of his own collection, which was later incorporated into the herbarium P (Stafleu and Cowan 1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.). In the protologue of A. dioica, Kunth (1825Kunth KS. 1825. Euphorbiaceae. In: Humboldt FWHA, Bonpland AJA, Kunth KS. (eds.). Nova Genera et Species Plantarum. Paris, v. 4, p. 168-174.) presents an illustration and the location of the type collection (Jaen de Bracamoros Province), without collector and number data. In herbarium P, we found two specimens (syntypes) M.A. Bompland & A. Humboldt 3604 with the same location indicated by Kunth in the protologue. Thus, here we choose M.A. Bompland & A. Humboldt 3604 (P00634954) as the lectotype of A. dioica and as the illustration forms part of the original material, it remains a syntype.

Argythamnia dioica is known from only a few specimens and is one of the few species that presents a dioecious sexual system. New collections and field observations are still necessary to determine whether this species has variation in its sexual system, such as the cases of A. desertorum and A. malpighiacea, as pointed out by Külkamp et al. (2020 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.).

Selected specimens examined: PERU. AMAZONAS: Chachapoyas, Balsas, 1000 m, 14 Apr 1982, (fr.), I. Sanchez 2795 (SI, US). CAJAMARCA: Jaen, Pucará, 1000 m, 28 Dec 1999, (fl.) R. Rojas et al. 845 (NY). Santa Rosa: 1000 m, 22 Apr 1950, (fl.), F. Woytkowski 5733 (US).

9. Argythamnia erubescens J.R.Johnst., Proceedings of the American Academy of Arts and Sciences 40: 689. 1905. Ditaxis erubescens (J.R.Johnst.) Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 57. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Type: VENEZUELA. ILHA MARGARITA: 21 Aug 1903, J.R. Johnston 58 (lectotype designated here: GH [GH00045749]!, isolectotypes: F [F0056240F]!, K [K000600283]!, NY [NY00246258]!, US [US00109837]!). Remaining syntype: VENEZUELA. ILHA MARGARITA: El Valle, 22 Jul 1901, O.O. Miller & J.R. Johnston 213 (NY [NY00246257]!).

Description: Shrub dioecious, without woody tubers; stems erect, internodes 3-20 mm long; leaves not rosulate, blade 0.9-3.5 cm long, elliptic to lanceolate, margin serrulate, with 8-10 teeth; racemes 2-5 mm long, 1 pistillate flower, 2-4 staminate flowers, with sepals 3.9-4.1 mm long, pubescent on both surfaces, staminal column ca. 3.5 mm long, stamens 10, staminodes 4, pubescent; pistillate flowers with pedicel ca. 2 mm long, sepals 5, margin entire, petals 5, styles bifid.

Distribution and habitat: The species is endemic to the northern of Venezuela and restricted to Margarita Island (Fig. 2 C ), occurring in seasonally dry tropical forest, in the Venezuelan province.

Flowering and fruiting: Argythamnia erubescens has been collected fertile from June to December.

Notes: In the protologue of Argythamnia erubescens, Johnston (1905Johnston JR. 1905. Proceedings of the American Academy of Arts and Sciences 40: 1-689.) mentions two collections as type material (syntypes). Following art. 9.3 of the ICN, we chose J.R. Johnston 58 (GH00045749) as lectotype for the name. This is a rare species, and until now represented only by the type specimens in herbarium collections. Argythamnia erubescens is morphologically similar to A. polygama.

10. Argythamnia grazielae (Külkamp) Külkamp & Riina, Biology, 12(2):173. 2023Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... . Ditaxis grazielae Külkamp, Phytotaxa 455 (2): 152-160. 2020. Type: BRAZIL. BAHIA: Wanderley, 25 January 1996 (fl. fr.), B.R. Chagas s.n. (holotype: RB [RB00084882]!, isotypes: CEPEC [CEPEC131190]!, K [K001206888]!, MG!, NY [NY01183998]!, SPF [SPF196837]!).

Description: Herbs not acaulescent to subshrubs, monoecious, without woody tubers; stems erect, internodes 5-35 mm long; leaves not rosulate, blade 1.8-6.5 cm long, lanceolate, margin serrate to serrulate, 20-34 teeth; racemes 4-7 mm long, 1 pistillate flower, basal, 7-10 staminate flowers, distal, sepals 3.1-3.2 mm long, staminal column 1.2-1.5 mm long, stamens 10, staminodes 4, pubescent; pistillate flowers with pedicel 1.5-2.5 mm long, sepals 5, margin serrate, petals 5, 1.5-2 mm long, styles bifid.

Distribution and habitat: Argythamnia grazielae is endemic to the state of Bahia, in Brazil (Fig. 2 C ); has been collected in environments with anthropogenic disturbances and in the understory of open arboreous Caatinga, at elevations from 470 to 800 meters. This region is classified in the Caatinga province, one of the largest seasonally dry tropical forest areas in South America (Särkinen et al. 2011Särkinen T, Iganci JRV, Linares-Palomino R, Simon MF, Prado DE. 2011. Forgotten forests-issues and prospects in biome mapping using seasonally dry Tropical Forests as a case study. BioMed Central Ecology 11: 27.).

Flowering and fruiting: Flowers and fruits can be found throughout the year, but especially after rainy periods.

Notes: This species occurs in the same area as A. desertorum and A. malpighiacea, but is morphologically similar to A. alcalina (Minas Gerais and Goiás states, Brazil) and A. argothamnoides (Venezuela). Phylogenetically, A. grazielae is sister to A. alcalina, and both form a clade with the other species of the Caatinga (Külkamp et al. 2023 a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.).

Selected specimens examined: BRAZIL. BAHIA: Juazeiro, Distrito de Massaroca, Caatinga, 9°50’53”S, 40°19’5”W, 470 m, 12 Jun 2009, (fl. fr.), E. Melo et al. 6325 (HUEFS). Jussara, Toca, Propriedade de Lindomar, 11°05’58”S, 41°55’18”W, 18 Dec 2018 (fl.), J. Külkamp et al. 689 (MEXU, R, RB, SPF). Morro do Chapéu, APA Gruta dos Brejões, Vereda do Romão Gramacho, 2 Oct 2009 (fl. fr.), R.F. Machado 417 (HUEFS). São Gabriel, Fazenda Boa Sorte, area antropizada, 11°1’S, 41°39’W, 800 m, 5 Apr 2009 (fl. fr.), R.F. Machado et al. 205 (HUEFS).

11. Argythamnia illimaniensis (Baill.) Müll.Arg., Linnaea 34: 146. 1865. Ditaxis illimaniensis Baill., Étude générale du groupe des Euphorbiacées 299. 1858. Type: BOLIVIA. COTAGNA: Vallée Chaude au pied de l’Illimani, 1839, J.B. Pentland 34 (lectotype designated here: P [P00634957]!, isolectotype: P [P00634956]!).

Description: Shrub dioecious, without woody tubers; stems erect, internodes 1.2-20 mm long; leaves not rosulate, petiole ca. 10 mm long, blade 0.9-3.2 cm long, lanceolate, margin serrate, 5-9 teeth, rarely entire; racemes ca. 3 mm long, 1 pistillate flower, 2 staminate flowers with sepals ca. 3.5 mm long, pubescent on abaxial surface, staminal column ca. 2 mm long, stamens 10, staminodes 5, pubescent; pistillate flowers with pedicel 1-1.8 mm long, sepals 5, margin entire, petals 5, styles bifid.

Distribution and habitat: Argythamnia illimaniensis is endemic to northern Bolivia (Fig. 2 A ), occurring in arid regions with shrubby vegetation, in the Yungas province.

Flowering and fruiting: The period of flowering and fruiting is not known.

Notes: Baillon (1858Baillon HE. 1858. Estude Générale du Groupe des Euphorbiacées. Paris, Masson. ) presented a description of the genus Ditaxis and included only a species list with their type specimens, without any descriptions. For A. illimaniensis the author mentions Pentland 4, but analyzing this collection, we found that it belongs to Solanum corymbosum Jacq. Later, Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) described A. illimaniensis and indicated the specimen J.B. Pentland 34 as type. Here we accept this specimen as the type of the name, as it is the only collection of Argythamnia made by Pentland. In the P herbarium there are two syntypes J.B. Pentland 34, and here we chose the specimen P00634957 as lectotype of A. illimaniensis. This is a rare species, known only by the type from La Paz region in Bolivia, and is morphologically similar to A. breviramea.

12. Argythamnia jablonszkyana (Pax & K.Hoffm.) J.W.Ingram, Bulletin of the Torrey Botanical Club 84: 423. 1958. Ditaxis jablonszkyana Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 60. 1912. Type: ARGENTINA. CATAMARCA: Campo de Pilciao, Mar 1873, F. Schickendatz 229 (lectotype designated here: G [G00434847], isolectotypes: CORD [CORD00003090]!, GOET [GOET006401]!, K [K000600277]!). Remaining syntypes: ARGENTINA. CATAMARCA: Medanos del Pilciao, Jan 1876, F. Schickendatz 163 (CORD [CORD00003092]!). ARGENTINA. CATAMARCA: Pilciao, Dec 1872, F. Schickendatz 275 (CORD [CORD00003091]!).

Description: Herbs, monoecious, non-acaulescent, without woody tubers; stems erect, internodes 2-5 mm long; leaves not rosulate, blade 1-3.5 cm long, lanceolate to elliptic, margin entire; racemes 3-6 mm long, 1 pistillate flower, basal, 5-7 staminate flowers, distal, with 10 stamens, staminodes 2, glabrous; pedicel of the pistillate flower 1-2.5 mm long; pistillate flowers, sepals 5, ca 2.5 mm long, margin entire, petals 5, ca. 3.6 mm long, styles 3, entire, glabrous.

Distribution and habitat: Argythamnia jablonszkyana is endemic to northwest Argentina (Fig. 2 A ). It occurs in arid regions with shrubby vegetation at elevation from 800 to 1400 meters, in Monte province.

Flowering and fruiting: Flowering and fruiting from September to May.

Notes: Grisebach (1879Grisebach AHR. 1879. Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen. Göttingen, German .) described Aphora catamarcensis based on two collections that belong to two different species. Realizing this, Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.) proposed Ditaxis jablonszkyana based in part on the type material of the A. catamarcencis Pax & Hoffmann (1912). They included three different collections (syntypes), and we choose F. Schickendatz 229 (G00434847) as lectotype for the name. The other collections, F. Schickendatz 163 and F. Schickendatz 275 we treat as remaining syntypes.

Selected specimens examined: ARGENTINA. CATAMARCA: Andalgalá, 23 May 1943, (fl. fr.), H.H. Bartlett 20245 (NY, SI, US). LA RIOJA: Gral. Lavalle, Ruta Villa Unión a Patquia, Entre Pagancillo y El Balde, 1200 m, 15 Dec 1973, (fl. fr.), A.T. Hunziker 22428 (MBM, SI). SAN JUAN: Marayes, entre Marayes e lago salina de Mascasin pela ruta 141, margem da estrada (direito em direção ao lago) entre o km 94 e 95; 31^o28’9”S, 67^o13’1”W, 508 m, 26 Feb 2020, (fl. fr.), J. Külkamp 1246 (BA).

13. Argythamnia katharinae (Pax) Croizat, Ciencia (Mexico) 6(10-12): 353. 1946. Ditaxis katharinae Pax, Pflanzenr. IV.147.vi (Heft 57), 56. 1912. Type: PERU. CAJAMARCA: Pacasmayo, Los Reyes, 1000-1100 m, A. Weberbauer 4810 (lectotype designated here: MOL00002072!, isolectotype: MOL00002073!). Remaining syntype: PERU. CAJAMARCA: Pacasmayo, Los Reyes, 1000-1100 m, A. Weberbauer 4809 (no found).

Description: Shrub monoecious, without woody tubers; stems erect, internodes longer than ca. 12 mm long; leaves not rosulate, blade 3-5.5 cm long, obovate to obovate-lanceolate, margin with 12-22 teeth; racemes 5-12 mm long, 1 pistillate flower basal, 5-8 staminate flowers distally; sepals of staminate flower 8-9 mm long, stamens 10, staminodes 5, pubescent; pistillate flower with pedicel of 8-13 mm long, sepals 5, margin entire, petals 5, styles bifid, pubescent; seeds with smooth surface.

Distribution and habitat: Argythamnia katharinae is endemic to northwestern Peru (Fig. 2 C ). It occurs in shrubby vegetation and elevations ranging from 800 to 1100 meters, in the Puna province.

Flowering and fruiting: Flowering and fruiting in February.

Notes: Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.) indicated in the protologue of D. katharinae two syntypes as original material (A. Weberbauer 4809 and A. Weberbauer 4810). Both collections were in the herbarium B and were destroyed during World War II. Weberbauer’s main collections are at La Molina herbarium (MOL), and we found two specimens of A. Weberbauer 4810 and none under the number 4809. Here we choose the specimen A. Weberbauer 4810 (MOL0002072) as lectotype. Argythamnia katharinae is known from few specimens. Thus, field expeditions are necessary to understand the variation and conservation status of this taxon.

Selected specimens examined: PERU. CAJAMARCA: San Miguel, El Papayo, La Florida, 800 m, 1 Feb 1986, (fl.), S.L. Quiroz 1760 (F).

14. Argythamnia macrantha (Pax & K.Hoffm.) Croizat, Ciencia (Mexico) 6: 353. 1946. Ditaxis macrantha Pax & K.Hoffm., Pflanzenr. IV. 147. vii (Heft 63), 426. 1914. Type: ECUADOR. Agua Amarga. El Recreo, 15 Jan 1897, H.F.A. Eggers 15557 (lectotype designated here: US [US00109818]!, isolectotypes: F [F0056241F]!, GH [GH00047617]!, P [P04811592]!, S [S07-12980]!).

Description: Shrub, dioecious, without woody tubers; stems erect, internodes 2-25 mm long; stipules 1-2.5 mm long; leaves not rosulate, blade 2-8.7 cm long, obovate, margin serrate, 20-30 teeth, densely covered by malpighiaceous trichomes; racemes 4-9 mm long, 1-3 pistillate flowers, 3-7 staminate flowers with 10 stamens; pistillate flowers with a pedicel 6-10 mm long; sepals 5, margin entire, petals 5, 6-10 mm long, lanceolate, elliptic or oblanceolate, style and stigma ca. 3 mm long, styles bifid (with an inconspicuous second division at the apex), pubescent.

Distribution and habitat: Argythamnia macrantha is distributed in northwestern Peru and central-west Ecuador (Fig. 2 B ). This is the only species of the genus occurring in Ecuador, but the review of local herbaria and field expeditions may reveal the occurrence of other species, considering that there are poorly known areas of seasonal forest in the country. It occurs in shrubby and open arboreous vegetation at elevations ranging from 400 to 600 meters.

Flowering and fruiting: Flowering and fruiting in February.

Notes: Pax & Hoffmann (1914Pax F, Hoffmann K. 1914. Euphorbiaceae-Acalypheae-Mercu-rialinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV. 147 vii (Heft 63), 1-473.) described D. macrantha but did not indicate a main specimen. The description probably was based solely on the specimen deposited in the B herbarium, where the authors worked, but this collection was destroyed during World War II. Thus, it is necessary to choose a lectotype for the name. Here we designate the specimen H.F.A. Eggers 15557 (US00109818) as lectotype.

Selected specimens examined: PERU. TUMBES: Region del Pampa Hospital, 500 m, 10 Feb 1947 (fl. fr.), O.V. Nuñez 345 (US).

15. Argythamnia malpighiacea Ule, Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 42: 217. 1908. Ditaxis malpighiacea (Üle) Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 60. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Type: BRAZIL. PIAUÍ: Im Walde unterhalb der Serra da Lagoa, Jan 1907, E.H.G. Ule 7448 (lectotype designated by Külkamp et al. 2020 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.: HBG [HBG516356]!, isolectotypes: G [G00434846]!, K [K000600286]!).

Description: Subshrub to shrub, monoecious, without woody tubers; stems erect, internodes 3-30 mm long; leaves not rosulate, blade 1.5-7 cm long, ovate, lanceolate to elliptic margin entire; racemes 4-10 mm long, 2-3 pistillate flowers, 5-11 staminate flowers with 10 stamens, staminodes 3, pubescent; pistillate flowers with a pedicel 0.7-1.5 mm long, sepals 5, ca. 8 mm long, margin entire at anthesis, serrate in fruit, petals 5, ca. 1.7 mm long, styles bifid, pubescent.

Distribution and habitat: Argythamnia malpighiacea is endemic to northeastern Brazil (Fig. 2 A ). It occurs in shrubby and open arboreous vegetation at elevations ranging from 400 to 1150 meters, in the Caatinga province, one of the largest areas of the Seasonally Dry Tropical Forest biome.

Flowering and fruiting: Flowers and fruits throughout the year, usually blooming after the rains, in January to June.

Notes: This is an endangered (EN) species (Külkamp et al. 2020 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz JFA. 2020b. Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species. Phytotaxa 455: 152-160.), since its habitat is under constant anthropogenic pressure and the main threat is the severe fragmentation of the environment.

Selected specimens examined: BRAZIL. BAHIA: Abaíra, 13°14’00”S 41°51’00”W, 12 Mar 1992, (fl. fr.), B. Stannard 51884 (HUEFS); Mucugê, 13°08’24”S 41°23’08”W, 16 Dec 2018, (fl.), J. Külkamp et al. 658 (RB). CEARÁ: Baturité, 4°19’58”S 38°52’26”W, 12 Apr 1909, (fr.), A. Ducke 1982 (RB). MINAS GERAIS: Jaíba, 15°16’39”S 43°23’55”W, 22 Apr 2006, (fl. fr.), D.S. Carneiro- Torres 737 (HUEFS).

16. Argythamnia malpighipila (Hicken) J.W.Ingram, Bulletin of the Torrey Botanical Club 84: 423. 1958. Croton malpighipilus Hicken, Physis. Revista de la Sociedad Argentina de Ciencias Naturales 2: 106. 1916. Ditaxis malpighipila (Hicken) L.C. Wheeler, Contributions from the Gray Herbarium of Harvard University 124: 39. 1939. Type: ARGENTINA. RIO NEGRO: General Roca, 250-360 m, Sep 1914 to Feb 1915, W. Fischer 190 (lectotype designated here: SI [SI001366]!, isolectotypes: BKL [BKL00000632]!, CM [CM1260]!, F [F0056160F]!, GH [GH00047338]!, K [K000574047]!, NY [NY03932713]!, SI [SI001367]!, SI [SI001368]!, SI [SI001369]!, SI [SI001370]!, US [US00109610]!).

Description: Subshrub, dioecious, without woody tubers; stems prostrate, internodes 0.3-0.5 mm long; leaves not rosulate, blade 0.5-0.7 cm long, elliptic, margin entire; inflorescences 1.5-2 mm long, pistillate flower solitary, staminate flowers solitary or rarely 2-5, with 10 stamens, 3 staminodes, glabrous; pistillate flowers, sepals 5, margin entire petals 5, styles connate to apex, pubescent.

Distribution and habitat: Argythmania malpighipila is endemic to Argentina (Fig. 2 A ), and the middle Andes Mountain range is the area with most records, from 400 to 1700 meters. It occurs in arid open areas, usually on rocky plateaus with red soil, in the Monte province.

Flowering and fruiting: Flowers and fruits from November to March.

Notes: Hicken (1916Hicken CM. 1916. Physis. Revista de la Sociedad Argentina de Ciencias Naturales 2: 1-106.) described Croton malpighipilus (basionym of Argythamnia malpighipila) based on W. Fischer 190. The author does not mention the collection location nor the herbarium where the specimen is deposited. In an exhaustive search, we located 12 W. Fischer 190 specimens (syntypes) with the collection site as Rio Negro, Argentina. There are five duplicates at the San Isidro (SI) herbarium (Instituto de Botánica Darwinion), where Hicken worked during the time that the taxon was described. Here we chose the specimen W. Fischer 190 (SI001366) as the lectotype.

This species’ peculiar growth form has attracted the attention of botanists because it generally does not exceed 30 cm tall and has a thickened stem with a diameter of 4-10 cm. The architecture of the branches makes the plants resemble cushions in the desert, as mentioned on herbarium labels and observed in the field. This species is sister to A. jablonszkyana, and they form the clade sister to all other South American Argythamnia (Külkamp et al. 2023 a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.).

Selected specimens examined: ARGENTINA. BUENOS AIRES: Despeñadero, 15 Feb 1945, (fl.), R. Huidobro 1249 (US). MENDONZA: Potrerillos, Montanhas entre Ruta 7, Av. Los Condores (89) e Lago, 32^o57’24”S 69^o12’31”W, 1503 m, 24 Feb 2020, (fl.), J. Külkamp 1245 (BA). RIO NEGRO: General Roca, 57 km N de Barda del Medio por Ruta Nac. 151, 400 m, 7 Dec 1997, (fr.) R.H. Fortunato et al. 5720 (NY). SAN JUAN: Valle Fertil, Ruta 150, Ischigualasto (reserva provincial), subiendo la Formación Los Colorados desde el Rio de La Sal, 27 Dec 1997, (fl. fr.), F. Biurrun et al. 5007 (SI).

17. Argythamnia montevidensis (Didr.) Müll.Arg., Linnaea 34: 147. 1865. Stenonia montevidensis Didr. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening i Kjøbenhavn 148: 1857. Ditaxis montevidensis (Didr.) Pax, Die Natürlichen Pflanzenfamilien 3(5): 45. 1890. Type: URUGUAY. MONTEVIDEO: C.F.E. Otto s.n., (holotype C (mounted on 2 sheets) [C10011214]!, C [C10011215]!).

= Ditaxis trinervia Baill., Adansonia 4: 271. 1864. Type: BRAZIL. RIO GRANDE DO SUL: 1824, F. Sellow s.n. [correct: F. Sellow d 1011] (lectotype designated by Külkamp et al. (2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ): P [P04811562!]; isolectotypes: BR [BR590560]!, C [C10011214]!, G [G00434845]!, G [G00434844]!, P [P04811566]!, TUB [TUB009143]!, W [W0060337!]). Remaining syntype: URUGUAY. Banda Oriental del Uruguay, St.-Hilaire, A. C2-2456 (P [P04811555]!). Additional information: There are photographs of the destroyed type specimen at F 211525 and NY.

=Ditaxis triplinerviaKlotzsch, Arch. Naturgesch. 7: 199. 1841Klotzsch JF. 1841. Neue und weniger gekannte siidamerikanische Euphorbiaceen - Gattungen. Archiv für Naturgeschichte 7-1: 175-204.. (not validly published).

= Aphora catamarcensis Griseb. Abh. Königl. Ges. Wiss. Göttingen 24: 58. 1879. Argythamnia catamarcensis (Griseb.) Hieron. Bull. Acad. Nac. Cordova 4: 449. 1881. Ditaxis catamarcensis (Griseb.) Pax, Nat. Pflanzenfam 3(5): 45. 1890. Type: ARGENTINA. CATAMARCA: Quebrada de Tala, Nov 1872, Lorentz, P.G. & Hieronymus, G. 477 (lectotype designated by Külkamp et al. (2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... )): GOET [GOET006400]!, isolectotypes: CORD [CORD00005966!], GOET [GOET006399]!, K [K000600276]!). Additional information: Photographs of the type specimen destroyed exist at the F 211516 and NY.

Description: Herb not acaulescent to subshrub, monoecious, without woody tubers; internodes 8-32 mm long; leaves not rosulate, blade 0.8-5.2 cm long, lanceolate to elliptic, margin serrate, 2-10 teeth; inflorescences 6-9 mm long, 1 pistillate flower basal, 2-5 staminate flowers distal, with 8 stamens in two whorls (5+3), staminodes 3, glabrous; pistillate flowers, sepals 5, margin entire, petals 5, styles bifid, pubescent.

Distribution and habitat: Argythamnia montevidensis is distributed in Argentina, Bolivia, Brazil, Paraguay and Uruguay (Fig. 2 B ). Its occurs in open areas of the Chaco and Pampa provinces associated with sparse tree vegetation, at elevations ranging from 300 to 800 meters.

Flowering and fruiting: Argythamnia montevidensis has been collected fertile throughout the year.

Notes: Argythamnia montevidensis presents great morphological variation depending on the environment in which it occurs across its range. After analyzing the type specimens, Külkamp et al. (2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ) observed that the morphology of Argythamnia catamarcensis and A. montevidensis strongly overlap, so they treated A. catamarcensis as a new synonym for A. montevidensis. The species is similar to A. salina but can be distinguished by being exclusively monoecious, while A. salina is dioecious. The lectotypification of Argythamnia trinervia was detailed by Külkamp et al. (2023b).

Selected specimens examined: ARGENTINA. CATAMARCA: Alredores de Capital, 6 May 1910, (fl. fr.), Castillon 1565 (NY, US). CORDOBA: Cordoba. Chacra de La Merced, cerca del Puente Negro, 16 Nov 1949, (fl. fr.), A.T. Hunziker 8094 (CORD); Parque Sarmiento, bosque nativo, 31°25’50”S, 64°10’20”W, 27 Feb 2020, (fl. fr.), J. Külkamp 1250 (BA). CORRIENTES: Maraetá. Ruta 14, Caminho antes de Maraetá, 27 Apr 1953, (fl. fr.), E.G. Nicora 6360 (SI). JUJUY: Capital. Santo Domingo, entre El Bordo y El Barrial, 20 Apr 1955, (fr.), A.T. Hunziker 11017 (RB); La Rioja: Angel V. Peñaloza. Ruta 29, al Sur de Punta de los Llanos, entre el desvio a Tama y Carrizal, 19 Mar 1960, (fl. fr.), A.E. Cocucci et T.E. Fulvio 16087 (CORD). SALTA: Anta. San Severo, 35 km al NE de J.V. Gonzales, ruta 44, 320 m, 14 Feb 1984, (fl.), C.S. Toledo 863 (SI). San Luis: Altos Ponchos. Feb 1914, (fl. fr.), B. Carette 82 (SI). SANTIAGO DEL ESTERO: Espada. 10 Jan 1939, (fl. fr.), J.L. Argañarás 148 (SI). TUCUMAN: Burruyacú. Cerro del Campo, 800 m, 1928, (fl. fr.), S. Venturi 7660 (SI, US); BOLIVIA. SANTA CRUZ: Cordillera. Parque Nacional Kaa-Iya del Gran Chaco, alrededores del Puesto Militar 27 de Noviembre, rodeado de bosque chaqueño xérico, 15 Sep 1998, (fl. fr.), A.F. Fuentes 2544 (MO). BRAZIL. MATO GROSSO DO SUL: Porto Murtinho, Apr 2001, A. Pott et al. 8878 (HMS, RB); RIO GRANDE DO SUL: Barra do Quaraí. Parque Estadual do Espinilho, 30°11’28”S, 57°31’30”W, 12 Oct 2017, (fl. fr.), J. Külkamp et al. 367 (ICN, RB); PARAGUAY. BOQUERÓN: Rio Pilcomayo, 1888-1890, (fl.), T. Morong 996 (NY, US935668, US209700); CHACO: Agua Dulce. 4 Oct 1979, (fl. fr.), A. Schinini et E. Bordas 18064 (SI). Gran Chaco: Loma Clavel, Nov 1903, (fl. fr.), E. Hassler 2471 (F). URUGUAY. MONTEVIDEO: Montevideo. 1 Feb 1877, (fl. fr.), Fruchat s.n. (US28124490). RIO NEGRO: Campos Mafalda, ruta 24, km 46, 32°51’S, 58°00’W, 5 Feb 1997, (fl. fr.), E. Marchesi et M. Vignale s.n. (MVFA26641). SORIANO: Vera, no date, (fl. fr.), M. Berro 48 (MVM).

18. Argythamnia polygama (Jacq.) Kuntze, Revisio Generum Plantarum 2: 594. 1891. Croton polygamus Jacq., Enumeratio Systematica Plantarum, quas in insulis Caribaeis 32. 1760. Ditaxis polygama (Jacq.) L.C.Wheeler, Contributions from the Gray Herbarium of Harvard University 124: 39. 1939. Type: VENEZUELA. CARTHAGENAE [CARTAGENA]: (Not found).

= Ditaxis lancifolia Schltdl., Linnaea 26: 635. 1855. Argythamnia lancifolia (Schltdl.) Müll.Arg., Linnaea 34: 145. 1865. Type: VENEZUELA. Curucuti, 2000 m, H. Wagener 320 (Not found).

=Ditaxis glabella Griseb., Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen 7: 171. 1857. Type: VENEZUELA. GUADALUPE: F.E.P. Duchassaing s.n. (holotype (mounted on 2 sheets): GOET [GOET006396]!, GOET [GOET006397]!).

Description: Subshrub dioecious, without woody tubers; stems erect, internodes 7-37 mm long; stipules ca. 3 mm long; leaves not rosulate, blade 3-11 cm long, elliptic to oblanceolate, margin serrate, 9-25 teeth, malpighiaceous trichomes present; inflorescences 5-9 mm long, 1 basal pistillate flower, 2-5 distal staminate flowers, with 10 stamens, staminodes 4, pubescent; pistillate flowers with pedicels 10-20 mm long, sepals 5, margin entire, petals 5, ca. 7 mm long, lanceolate to elliptic, style and stigma ca. 1.5 mm long, styles bifid, pubescent.

Distribution and habitat: Argythamnia polygama is distributed in northern South America in Colombia and Venezuela (Fig. 2 A ), Central America (Panama), and the West Indies (Trinidad and Tobago). It occurs in seasonally dry shrubby and arboreal vegetation, at elevations ranging from 15-400 meters.

Flowering and fruiting: Flowers and fruits from November to June.

Notes: Jacquin (1760Jacquin NJ. 1760. Enumeratio Systematica Plantarum, quas in insulis Caribaeis. Leiden.) described Croton polygamus, however did not mention type specimen in the protologue. Later, in the study “Selectarum stirpium Americanarum Historia”, Jacquin (1763Jacquin NJ. 1763. Selectarum stirpium Americanarum historia. Viena.) cites as the type local “Carthagenae”. According to D’Arcy (1970D’Arcy W. 1970. Jacquin Names, Some Notes on Their Typification. Taxon 19: 554-560.), Jacquin collected several plant specimens on his trip to the West Indies, and many were grown in the Vienna Garden by him and used for later descriptions. According to Stafleu & Cowan (1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.), Jacquin herbarium collection was acquired by Joseph Banks and currently is part of the BM herbarium, but duplicates are in other European herbaria. According to these authors, specimens collected by Jacquin in the West Indies are rare in the BM herbarium, which was confirmed by us after exhaustive search at the mentioned and other herbarium collections. To date, no original material of Jacquin has been found, and additional research is needed in order to conduct a secure typification for this name.

Schlechtendal (1855Schlechtendal DFL. 1855. Euphorbiaceae. Linnaea 26: 1-808.) described Ditaxis lancifolia based on the collection H. Wagener 320 from Colombia, but the specimen was not found. A few collections of Wagener are housed at B, HAL and W herbaria, but none of them belong to Argythamnia or Ditaxis. As in the case of A. polygama, due to the lack of material, we will not designate a type without further information.

Some botanists consider A. lancifolia as the accepted name (Pax & Hoffmann 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.). However, despide that no type was indicated for the basionym of A. polygama (Croton polygamus), it has priority since the protologue has a brief description validating the name.

Grisebach (1857Grisebach AHR. 1857. Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen. Göttingen, German.) described D. glabella based on the specimen F.E.P. Duchassaing s.n., from his collection, today incorporated at GOET herbarium. The type consists of two sheets with one label. We here consider it as a single specimen mounted on two complementary sheets, and we recognize it as the holotype for the name. This binomial is validly published and we agree with Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.) that it is a synonym of A. polygama.

Argythamnia polygama is similar to A. acutangula, A. katharinae and A. macrantha. Therefore, more studies, including field expeditions, are necessary for a better understanding of the relationship among these taxa. In the phylogeny of Külkamp et al. (2023 a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.), only A. polygama was sampled, showing that the northern region of South America is the greatest gap in knowledge and sampling of the genus.

Selected specimens examined: COLOMBIA. ATLANTICO: Usiacurí, Caminho de Isabel Lopez, 100 m, 6 Jan 1940, (fl.), A. Dugand et H.G. Barriga 2322 (US). MADALENA: Santa Marta, 1898-1901, (fl.), H. Smith 2072 (US). VENEZUELA. CARABOBO: Cristobal Colon: 22 Feb 1923, (fl. fr.), W.E. Broadway 111 (US). Hacienda Taborda, near El Palito na rodovia de Valencia para Puerto Cabello, 0-200 m, 31 Dec 1917, (fl.), H. Pittier 7682 (US). NOVA ESPARTA: Tragaplata, Dec 1951, (fl.), H. Gines 2823 (US).

19. Argythamnia purpurascens S.Moore, Transactions of the Linnean Society of London, 2nd series: Botany 4: 466. 1895. Ditaxis purpurascens (S.Moore) Pax & K.Hoffm., Pflanzen. IV.147.vi (Heft 57), 61. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Type: BRAZIL. MATO GROSSO DO SUL: Corumbá, Jan 1892, S. Moore 959 (holotype: BM [BM000947420]!, isotype: NY [NY00246260]!). The specimen at B was destroyed, but there is a pictured at the Field Museum (F0BN005232).

= Ditaxis malmeanaPax & K.Hoffm., Pflanzen. IV.147.xvii (Heft 85), 179. 1924Pax F, Hoffmann K. 1924. Euphorbiaceae. In: Engler, A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV. 147 xvii (Heft 85), 1-179.. Type: BRAZIL. MATO GROSSO DO SUL: Corumbá. 6 Apr 1903, G.O. Malme 3049 (lectotype designated here: S [S07-12640]!, isolectotypes: GH [GH00047618]!, S [SR-10594]!); Remaining syntype: BRAZIL. MATO GROSSO DO SUL: Corumbá. 18 Dec 1902, G.O. Malme 2722 (S [S18-24591]!), syn. nov.

Description: Subshrub monoecious, without woody tubers; stems erect, internodes 5-28 mm long; leaves not rosulate, blade 1.5-11 cm long, ovate to elliptic, margin serrate, 19-35 teeth; inflorescences 4.5-6.7 mm long, 1 basal pistillate flower, 3-8 distal staminate flowers, with sepals 1.5-2.8 mm long, stamens 10, staminodes 4, glabrous; pistillate flowers with pedicel ca. 2 mm long, sepals 5, margin entire, petals 5, ca. 0.3 mm long, styles bifid or trifid, pubescent.

Distribution and habitat: Until the present study A. purpurascens was known only from a small region (Corumbá and Ladário municipalities) in the western state of Mato Grosso do Sul, Brazil, and therefore considered as endemic. However, a recent collection made in Puerto Quijarro, Bolivia (S.G. Beck 27535 [LPD, MA]) expanded the range of the species (Fig. 2 A ) and corresponds to the first record of the species from Bolivia. It is restricted to limestone soils and understory of seasonally dry tropical forests, at elevations of 200-300 meters.

Flowering and fruiting: Flowers and fruits from June to December.

Notes: Moore collected many plant specimens during his expedition through South America, and later he worked on their descriptions at the BM herbarium. We agree that the specimen S. Moore 959 (BM000947420) is the holotype of A. purpurascens. Since Ingram labeled the duplicate (NY00246260) as isotype, he therefore considered the BM specimen as the holotype. Moore worked principally at the collection of the herbarium BM. After carefully analyzing the type specimens, descriptions, and adittional specimens, we conclude that A. malmeana is a synonym of A. purpurascens and is presented here as a new synonym.

Pax & Hoffmann (1924Pax F, Hoffmann K. 1924. Euphorbiaceae. In: Engler, A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV. 147 xvii (Heft 85), 1-179.) described D. malmeana based on two collections (syntypes) mentioned in the protologue (G.O. Malme 3049 and G.O. Malme 2722). Here we choose the specimen G.O. Malme 3049 (S07-12640) as the lectotype of the name, and we treat G.O. Malme 2722 as remaining syntype.

Selected specimens examined: BOLIVIA. SANTA CRUZ: Puerto Quijarro, 6 km hacia Puerto Suarez (de arroyo Concepcion), 9 Set 2000, (fl. fr.) S.G. Beck 27535 (LPD, MA). BRAZIL. MATO GROSSO DO SUL: Corumbá, Bairro Universitário, próximo ao Campus da UFMS, entrada que leva ao porto limoeiro, 26 Aug 2018, (fl. fr.), J. Külkamp 512 (COR, RB). Ladário, Fazenda Uruba, primeira lage, 8 Nov 1996, (fl. fr.), V.J. Pott, A.M. Gonzales et A.L. Sanches 3251 (CPAP).

20. Argythamnia salina (Pax & K.Hoffm.) J.W.Ingram, Bulletin of the Torrey Botanical Club 84: 423. 1958. Ditaxis salina Pax & K.Hoffm., Pflanzen. IV.147.vi (Heft 57), 72. 1912. Type: PARAGUAY. PARAGUARI: Salzige Standorte bei Mbay in der Umgebung von Paraguari, B. Balansa 3152 (lectotype designated by Külkamp et al. (2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... )): G [G00306964]!, isolectotypes: P [P00634961]!, P [P00634960]!).

Description: Subshrub, dioecious, with woody tubers; stems erect, internodes 7-50 mm long; leaves not rosulate, petioles absent to 1-15 mm long, blade 1.8-5.5 cm long, ovate to elliptic, margin entire to serrate, 8-12 teeth; inflorescences 9-40 mm long, (1)2 pistillate flowers, 15-35 staminate flowers, with 8 stamens, staminodes 2, glabrous, pistillate flowers, sepals 5, margin entire, petals 5, styles bifid, pubescent.

Distribution and habitat: Argythamnia salina occurs in northeastern Argentina, west of Brazil and Paraguay (Fig. 2 C ), in the Chaco province. This species occurs in grassland environments with clayey, moist, and saline soils.

Flowering and fruiting: Flowers and fruits from November to March.

Notes: It is a rare species, known from a few specimens, and recently two new records from the same area have been reported for Brazil (Külkamp et al. 2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ). Even with the expansion of the EOO, D. salina was preliminarily categorized as Endangered (EN), and the threats include severe fragmentation due to agricultural monocultures, continuous decline of the AOO, and loss of habitat quality in its range (Külkamp et al. 2023bRadcliffe-Smith A. 2001. Genera Euphorbiacearum. London, Royal Botanic Garden Kew.).

Selected specimens examined: ARGENTINA. CORRIENTES: Empedrado. Estancia Las Três Marias, 13 Mar 1954, (fl.) T.M. Pedersen 2638 (US); FORMOSA: Formosa, (fl.), P. Jorgensen 40684 (LIL, SI); Formosa. Jan 1918, (fr.), P. Jorgensen 2264 (BA, US). BRAZIL. MATO GROSSO DO SUL: Bela Vista. Rod. BR-267, próximo do trevo para Bela Vista, 16 Nov 2002, (fl. fr.), G. Hatschbach, M. Hatschbach et J.M. Silva 74272 (MBM); Bela Vista. próximo a entrada da Fazenda União, estrada MS-178 de Bonito a BR-267 para Porto Murtinho, 21°35’15”S, 56°39’34”W, 406 m, 16 Nov 2002, (fr.) A. Pott et al. 10785 (CPAP).

21. Argythamnia sellowiana (Pax & K.Hoffm.) J.W.Ingram, Bulletin of the Torrey Botanical Club 84: 423. 1958. Ditaxis sellowiana Pax & K.Hoffm., Pflanzen. IV.147.vi (Heft 57), 77. 1912. Neotype designated by Külkamp et al. (2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ): BRAZIL. RIO GRANDE DO SUL: Bagé, Próximo ao trevo, 55^o49’46’’W, 29^o48’32”S, Nov 2017, J. Külkamp et al. 394 (RB 827128!, isoneotype: ICN [ICN197214]!).

=Argythamnia rhizantha (Pax & K.Hoffm.) J.W.Ingram, Bull. Torrey Bot. Club 84: 423. 1958. Ditaxis rhizantha Pax & K.Hoffm., Pflanzenr. 4: 77. 1912. Paxia rhizantha (Pax & K.Hoffm.) Herter, Estud. Bot. Reg. Uruguay 4: 80. 1931. Paxiuscula rhizantha (Pax & K.Hoffm.) Herter, Revista Sudamer. Bot. 6: 93. 1939. Neotype designated by Külkamp et al. (2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ): URUGUAY. RIVERA: Cerro Aurora, 10-12 Feb. 1961, Arrillaga et al. 1137 (MVFA!).

=Argythamnia rosularis (Pax & K.Hoffm.) J.W.Ingram, Bull. Torrey Bot. Club 84: 423. 1958. Ditaxis rosularis Pax & K.Hoffm., Pflanzenr. 4: 76. 1912. Paxia rosularis (Pax & K.Hoffm.) Herter, Estud. Bot. Reg. Uruguay 4: 80. 1931. Paxiuscula rosularis (Pax & K.Hoffm.) Herter, Revista Sudamer. Bot. 6: 93. 1939. Neotype designated by Külkamp et al. (2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ): ARGENTINA. MISSIONES: Bonpland, 15 Dec 1909, Jörgensen, P. 667 (BAB [BAB31210]!).

Description: Herbs, monoecious, with woody tubers; stems prostrate; internodes 0.1-0.5 mm long; leaves rosulate, blade 2-9 cm long, elliptic to obovate, margin entire; inflorescences 4-6 mm long, 1 pistillate flower, basal, 3-5 staminate flowers, distal, stamens 8, staminodes absent, pistillate flowers, sepals 5 (6), 5.9-8.5 mm long, falcate, margin entire, petals 5, styles bifid, pubescent.

Distribution and habitat: Argythamnia sellowiana occurs in northeastern Argentina, south of Brazil and north of Uruguay (Fig. 2 A ), a region in the Chaco and Pampa provinces. The information on specimens labels indicates that the species is associated with grasslands and rocky outcrops, not occuring in shady locations.

Flowering and fruiting: Flowers and fruits from October to March.

Notes: This species is morphologically very close to and occurs in sympatry with A. acaulis. A detailed discussion about them is presented in Külkamp et al. (2023 b Külkamp J, Iganci JRV, Cordeiro I, Baumgratz J. 2023b. Argythamnia (Euphorbiaceae) from biogeographic provinces of the Chaco and Pampa in South America. Brittonia 75: 393-410. doi: 10.1007/s12228-023-09758-8.
https://doi.org/10.1007/s12228-023-09758... ). In the phylogenetic reconstruction of Külkamp et al. (2023aKülkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.), A. sellowiana emerges as sister to the Chaco and Pampa species, A. salina and A. montevidensis. However, A. acaulis was not sampled.

Selected specimens examined: ARGENTINA. CORRIENTES: Ituzaingó. Playadito, 20 km W de Apóstoles, 1879, (fl. fr.), A. Schinini 21790 (CTES). Mercedes. Estancia Itá Caabó, 21 Mar 1956, (fl. fr.), T.M. Pedersen 3807 (NY, US). ENTRE RIOS: Colón. Palmar de Colón, 58^o15’36”W, 31^o52’48”S, A. Burkart s.n. (SI). MISSIONES: Candelária. Bonpland, alrededores de balneario municipal, 57^o27’36”W, 27^o29’05”S, H.A. Keller s.n. (SI). BRAZIL. RIO GRANDE DO SUL: Alegrete. Beira da BR 290, próximo do arroio Lageadinho, cerca de 15 km após Alegrete em direção a Rosário, alto da primeira colina, 12 Feb 1990, (fl. fr.), D.B. Falkenberg 5287 (FLOR); Arroio dos Ratos. Estrada do Faxinal, Fazenda Esperança, 30^o16’22”S, 51^o43’12”W, 15 Mar 2018, (fl. fr.), J. Külkamp et G.P. Coelho 466 (ICN). Caçapava do Sul. Guaritas, Topo da Guarita, 30^o50’19”S, 53^o30’07”W, 10 Oct 2017, J. Külkamp et al. 342 (ICN). PARAGUAY. GUAIRA: Villarica. Feb 1931, (fl. fr.), P. Jörgensen 7352 (F, NY). URUGUAY. ARTIGAS: Rivera. Parque Gran Bretanha, 5 Feb 1989, (fl. fr.), A.E. Paz 567 (MVM); Cerro Aurora, 10-12 Feb 1961, (fl. fr.), Arrillaga et al. 1137 (MVFA).

22. Argythamnia simoniana (Casar.) Müll.Arg., Linnaea 34: 145. 1865. Ditaxis simoniana Casar., Novarum Stirpium Brasiliensium Decades 10: 87. 1845. Type: BRAZIL. RIO DE JANEIRO: “Reperi in sylvis caeduis montis Corcovado prope Rio de Janeiro”. Oct 1839, G. Casaretto 1840 (lectotype designated by Delprete et al. 2019Delprete GP, Baldini RM, Fumeaux N, Guglielmone L. 2019. Typification of plant names published by Giovanni Casaretto based on specimens collected in Brazil and Uruguay. Taxon 68: 783-827.): TO [mounted on 6 sheets] not seen, isolectotype: G-DC [G00313059]!).

=Ditaxis melochiiflora Baill., Adansonia 4: 270. 1864. Type: BRAZIL. RIO DE JANEIRO: Capueiras prés dÚba, 1816-1821, A. Saint-Hilaire A1-540 (lectotype designated here: P [P00634962]!, isolectotypes: F [F0056242F]!, P [P00634963]!, P [P00634964]!).

Description: Subshrub to shrub monoecious, without woody tubers; stems erect, internodes 9-55 mm long; leaves not rosulate, pedicel scar not evident, blade 3-15 cm long, elliptic to lanceolate, margin entire, rarely toothed; inflorescences 3-8 mm long, 1 pistillate flower, basal, 4-10 staminate flowers, distal; staminate flower with sepals ca. 3.5 mm long, stamens 10, staminodes 4, pubescent, pistillate flower with pedicel 7-23 mm long, sepals 5, 9-12 mm long, margin entire, petals 5, styles bifid, pubescent; seed with reticulated surface.

Distribution and habitat: Argythamnia simoniana is endemic to the state of Rio de Janeiro, Brazil (Fig. 2 A ). It occurs in the understory of forests restricted to rocky inselbergs along the ocean coast, a region in the Atlantic province.

Flowering and fruiting: Flowers and fruits throughout the year.

Notes: Argythamnia simoniana was described based on collections acquired in Rio de Janeiro by Casaretto during his expedition to Brazil. Delprete et al. (2019Delprete GP, Baldini RM, Fumeaux N, Guglielmone L. 2019. Typification of plant names published by Giovanni Casaretto based on specimens collected in Brazil and Uruguay. Taxon 68: 783-827.) lectotypified the name because no main specimen was indicated in the protologue, and the authors considered the six samples at TO herbarium as lectotype.

We analyzed the type specimens and original description of D. melochiiflora and agree that this name should be treated as a synonym for A. simoniana. Ditaxis melochiiflora was described by Baillon (1864Baillon HE. 1864. D’Observations Botaniques. Adansonia 4: 1-289.) based on the collection A. Saint-Hilaire A1-540. However, he did not indicate the repository herbarium. We found four specimens of this collection, and here we are recognizing A. Saint-Hilaire A1-540, (P00634962) as the lectotype of D. melochiiflora. Argythamnia simoniana is the only species of the genus that occurs in the state of Rio de Janeiro (Külkamp 2020 a Külkamp J, Iganci JRV, Cordeiro I. 2020a. Chiropetalum. In: Flora e Funga do Brasil . Rio de Janeiro, Jardim Botânico do Rio de Janeiro . http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB29160. 10 Oct. 2023.
http://floradobrasil.jbrj.gov.br/reflora... ). It is similar to the shrubby species of northern South America (A. acutangula, A. dioica, A. katharinae, A. macrantha, and A. polygama), but it can be differentiated by the reticulate surface and blackish color of the seeds (vs. smooth and gray color). The phylogenetic reconstructions of Külkamp et al. (2023a) show that A. dioica and A. polygama belong to the same clade as A. simoniana, and a close relationship is reinforced here based on morphology.

Selected specimens examined: BRAZIL. RIO DE JANEIRO: Cabo Frio, Reserva Tauá. Limite entre os municípios de Armação dos Búzios e Cabo Frio, 6 Jan 2018, (fl. fr.), L.J.S. Pinto 2013 (RB). Iguaba Grande, BR 116, 3 Oct 2012, (fl. fr.), L. Quintanilha 98 (RB). Niterói, Itaipu, Serra da Tiririca, 100 m, 16 Apr 2018, (fl. fr.), J. Külkamp et al. 483 (RB). Rio de Janeiro, Jardim Botânico, 18 Jul 1945, (fl. fr.), J.G. Kuhlmann s.n. (RB).

Chiropetalum A.Juss.

Chiropetalum A.Juss. in Ann. Sci. Nat. 25: 21. 1832.

Type: Chiropetalum lanceolatum (Cav.) A.Juss. (designated by O’Donell & Lourteig 1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ).

Herbs or subshrubs, perennial or rarely annual; monoecious, less commonly dioecious, gynodioecious, or androdioecious. Branches erect or decumbent, thorns absent, glabrous or covered by malpighiaceous, simple, or stellate trichomes. Stipules present, glabrous or covered by simple and/or malpighiaceous trichomes. Leaves simple, alternate, petiolate; venation pinnate, basal and suprabasal actinodromous, margin crenate, serrate, bisserrate or entire; glabrous or pubescent with trichomes malpighiaceous, simple, stellate. Raceme uni-bisexual, axillary; flowers 1-bracteolate; bracteole persistent, sessile, pubescent. Staminate flowers 3-35, positioned distally in the inflorescence, pedicel articulated; sepals 5, valvate, covered by simple and/or malpighiaceous trichomes; petals 5, glabrous, 3-7-lobed, free portion 1/3-1/2 of the petal length; floral nectaries 5, around the base of the staminal column, antessepalous, glabrous or pubescent; stamens 3-6, filaments partially joined together forming a column; anthers arranged in one whorl, basifixed. Pistillate flowers 1-6, proximal in the inflorescence; sepals 5, valvate, covered by simple and/or malpighiaceous trichomes; petals absent, rarely 5; floral nectaries 5, adhered to the receptacle, antessepalouss, glabrous or pubescent; ovary superior, subglobose, 3-locular, locules uniovulate; styles 3, bifid. Capsule 4-8 mm diam., dehiscent, covered by simple, glabrous or stellated and/or malpighiaceous trichomes. Seeds spherical, surface foveolate or rough, gray to black.

Twenty Chiropetalum species and one variety are recognized from South America, all endemic to the southern region of the Equator (Fig. 5). Here, we treat Aonikena patagonica Speg. in Chiropetalum as proposed by O’Donell & Lourteig (1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ), but we understand that molecular studies are needed to position the taxon properly in Ditaxeae. The southernmost distribution of the genus is represented by C. patagonicum (Speg.) O’Donell & Lourteig in Patagonia, Argentina (Fig. 5 A ), and northernmost by C. pavonianum (Müll.Arg.) Pax in Bagua, Peru (Fig. 5 C ). The greatest species richness is registered for Brazil, with eight species, followed by Argentina, with five species (Fig. 5). Chiropetalum species have a regionalized pattern of distribution, presenting many regional endemisms with reduced extent of occurrences. The most widely distributed species are C. patagonicum and C. griseum Griseb. (Fig. 5 A ) that occur in the southern and northern of Argentina, respectively, and C. tricoccum (Vell.) Chodat & Hassl. in eastern Brazil (Fig. 5 A ).

The highest concentration of collections for Chiropetalum is found in southern Brazil and northern and central Argentina (Fig. 3 A ). The number of records in southern Brazil is associated with the species richness in the region, eight species (Fig. 5), while northern and central Argentina species richness is mainly associated with the highly number of records of C. argentinense Skottsb., C. boliviense (Müll.Arg.) Pax & K.Hoffm. and C. griseum.

The southern half of the Andes has proven to be a barrier that separates the Chiropetalum species from the east and west. In this region it is not common to observe the occurrence of species at elevation above 1000 meters, unlike the species that occur in Bolivia and Peru, which are often found at elevation above 2500 meters. The Chiropetalum species of Argentina, Bolivia, Chile, and Peru occur in seasonally dry environments, while some Brazilian species occur in more humid and shaded environments. Chiropetalum may have diversified and adapted in these environments. In this context, we believe that biogeographic studies would elucidate this distribution pattern. Here, 10 lectotypes, one neotype, one status novum, and two new synonyms are presented for the Chiropetalum species occurring in South America.

Key to the species of Chiropetalum in South America

1. Leaves with stellate trichomes 2

1’. Leaves without stellate trichomes 9

2. Floral nectaries pubescent 3

2’. Floral nectaries glabrous 5

3. Staminate flowers with petals 5-6-lobed; stamens 3 (4-5) 26. C. boliviensis

3’. Staminate flowers with petals 3-5-lobed; stamens (4)5 4

4. Leaves ovate, margin 5-11 toothed; ovary densely covered by stellate trichomes, in addition to simple and malpighiaceous trichomes 30. C. griseum

4’. Leaves elliptic to ovate, margin 10-16 toothed; ovary densely covered by malpighiaceous trichomes, in addition to simple trichomes, stellate trichomes absent 35. C. pavonianum

5. Inflorescence with 2-7 staminate flowers; petals of staminate flowers 3-5 lobed; stamens 3-4 6

5’. Inflorescence with 8-48 staminate flowers; petals of staminate flowers 5-7 lobed; stamens (4)5(6) . 7

6. Ovary with stellate trichomes 39. C. ramboi

6’. Ovary without stellate trichomes 31. C. intermedium

7. Leaf with the adaxial surface flat (tertiary veins not evident); 1 inflorescence per node 38. C. quinquecuspidatum

7’. Leaf with the adaxial surface irregular undulate (tertiary veins conspicuous); 1-3 inflorescences per node 8

8. Style pubescent in basal half and glabrous in the apical half 33. C. molle

8’. Style pubescent to the apex 37. C. puntaloberense

9. Leaf margin with more than 10 teeth 10

9’. Leaf margin entire or serrate with 1-9 teeth 13

10. Staminate petals 3-lobed; floral nectaries glabrous 11

10. Staminate petals 4-7-lobed; floral nectaries pubescent 12

11. Leaf base rounded, covered by malpighiaceous trichomes 41. C. tricoccum

11’. Leaf base subcordate, covered by simple and malpighiaceous trichomes 23. C. anisotrichum

12. Leaves covered by malpighiaceous trichomes 32. C. latifolium stat. nov.

12’. Leaves covered by simple and malpighiaceous trichomes 40. C. ruizianum

13. Leaves glabrous; petals of the staminate flowers unlobed with an undulate apex 34. C. patagonicum

13’. Leaves pubescent; petals of the staminate flowers deeply lobed 14

14. Leaf margin entire 15

14’. Leaf margin serrate 18

15. Leaves linear 24. C. argentinense

15’. Leaves elliptic, lanceolate, ovate or cordate 16

16. Inflorescence with 3-7 staminate flowers; petals of the staminate flowers 3-4-lobed 28.C. cremnophilum

16’. Inflorescence with 8-40 staminate flowers; petals of the staminate flowers 4-5-lobed 17

17. Leaves ovate; inflorescence with 10-40 staminate flowers 25. C. berterianum

17’. Leaves lanceolate to elliptic; inflorescence with 8-13 staminate flowers 27. C. canescens

18. Leaves covered only by malpighiaceous trichomes 19

18’. Leaves covered by simple and malpighiaceous trichomes 29. C. foliosum

19. Inflorescence glabrous; pistillate flowers without petals 36. C. phalacradenium

19’. Inflorescence pubescent; pistillate flowers with petals 42. C. tricuspidatum

23. Chiropetalum anisotrichum (Müll.Arg.) Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 93. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia anisotricha Müll.Arg. Flora Brasiliensis 11(2): 314. 1874. Type: BRAZIL. MINAS GERAIS: in silvis prope Lagoa Santa, Warming 1576 (lectotype designated by Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468: G [G00434178]!, isolectotypes: C [C10023218]!, C [C10023219]!, C [C10023220]!). Remaining syntypes: BRAZIL. MINAS GERAIS: in silvis prope Lagoa Santa, Warming 1617: C [C10023221]!, C [C10023222]!; Warming s.n.: GH [GH00045757]!, P [P04865025]!.

Description: Herb to subshrub; leaves ovate, subcordate base, covered by simple and malpighiaceous trichomes, stellate trichomes absent, margin with 14-26 teeth per side; inflorescence covered by simple trichomes, 1-5 pistillate flowers, 10-17 staminate flowers per inflorescence, floral nectaries glabrous in both staminate and pistillate flowers; staminate flowers with 3-lobed petals, stamens 5, pistillate flowers without petals, styles glabrous, ovary and fruit covered by simple and malpighiaceous trichomes.

Distribution and habitat: Until the present study, C. anisotrichum was thought to be endemic to Brazil, but during the review of herbaria collections, two specimens were identified from the province of Missiones, Argentina, being the first records. In Brazil, this species occurs in the states of Minas Gerais, Paraná, Rio Grande do Sul, and Santa Catarina (Fig. 5). It is found in the Atlantic Forest and Cerrado phytogeographical domains, at the edges and understory of riparian forests.

Flowering and fruiting: Flowers and fruits all year round, most frequently in Spring and Summer.

Notes: The protologue (Müller 1874Müller A. 1874. Euphorbiaceae. In: Martius CFP, Eichler AG. Flora Brasiliensis. 11, 2, 1-1752. ) indicates “Habitat in prov. Minas Gerais, in silva prope Lagoa Santa: Warming,” without mentioning a collection number. Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.) indicated Warming 1576 and 1617 as type materials, while Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) indicate Warming 1576 (G) as the holotype. Müller worked extensively in the Geneva herbarium, including the G-DC, G-BOIS, and G-BU collections, but he also had access to other European herbaria at the same time (Schultes 1953Schultes RE. 1953. Studies in the genus Hevea VII. Botanical Museum Leaflets, Harvard University 16: 21-44.). We cannot be certain that Müller analyzed all Warming specimens that we found in the herbaria C, G, GH, and P, with or without a collect number. Although Warming 1576 is the only specimen in G-DC, it is not specifically mentioned in the protologue. We believe that Müller analyzed more than one specimen for the description of the taxon, since the description is very complete, and it is evident that more than one specimen was used in the description and the specimens were already deposited in these other collections at that time. By indicating the specimen at G as a holotype, Ingram (1980b) made an “inadvertent lectotypification” for using the term holotype for a syntype (Prado et al. 2015Prado J, Hirai RY, Moran RC. 2015. Proposals concerning inadvertent lectotypifications (and neotypifications). Taxon 64: 651.). This inadvertent lectotypification is acceptable according to art. 9.23 ICN when published before 1 January 2001. According to art. 9.10 ICN, the use of the term “holotype” should be treated as an error to be corrected.

Selected specimens examined: ARGENTINA. MISIONES: Frontera. Bernardo de Irigoyen, 24 Jul 1945 (fl. fr.), J.H. Hunziker 949 (CORD); Dept. General Manuel Belgrano. 2 km S de Bernardo de Irigoyen, salto del Río Pepirí Guazú, 800 m, 15 Oct 1996 (fl. fr.), O. Morrone 1479 (SI). BRAZIL. MINAS GERAIS: Cardeal Mota, Limestone (marble) outcrop ca. 10 km S. of Serra do Cipó, 19 Feb 1972 (fl. fr.), W.R. Anderson et al. 36284 (HB, MBM, RB, US). PARANÁ: Campina Grande do Sul, sítio do Belizaro, 27 Dez 1966 (fl. fr.), G. Hatschbach 15552 (MBM, UPCB, US). RIO GRANDE DO SUL: Pareci Novo, Saindo da RS-124 percorrer 700 metros na estrada Montenegro-Mathias, beira da estrada próximo ao rio 29°38’43”S, 51°25’42”W, 07 May 2017 (fl. fr.), J. Külkamp et al. 222 (ICN). SANTA CATARINA: Florianópolis, Bairro Tapera, Trilha do morro dos Naufragados, 27°47’59.9”S, 48°33’53.35W”, 17 Nov 2016 (fl. fr.), J. Külkamp et al. 148 (ICN); São Miguel do Oeste, Margin Forest, Paraíso 26°34’S, 53°40’W, 21 Oct 1964 (fl. fr.), L.B. Smith et R.M. Klein 12774 (NY, US).

24. Chiropetalum argentinense Skottsb., Lilloa 17: 304. 1949. Argythamnia argentinensis (Skottsb.) Allem & Irgang. Revista Brasileira de Biologia 36(2): 286. 1976Allem AC, Irgang BE. 1976. Two new species of Argythamnia (Euphorbiaceae) from Rio Grande do Sul, Brazil. Revista Brasileira de Biologia 36: 283-287.. Type: ARGENTINA. CÓRDOBA: Rio Primero, Estancia, Feb 1905, T. Stuckert 14985 (holotype: LIL [LIL4785]!, isotypes: CORD [CORD00053057]!, GB [GB004-7686] fragment!).

= Chiropetalum tricuspidatum var. angustifolium Griseb., Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen 19: 97. 1874. Type: ARGENTINA. CORDOBA: In den Barrancas bei Córdoba zwischen Gebüsch [In the Barrancas near Cordoba between shrub], 1870, P.G. Lorentz 77 (lectotype designated here: GOET [GOET006402]!, isolectotypes: CORD [CORD00005947]!, GOET [GOET006403]!).

Description: Herb; leaves linear, base cuneate to truncate, pubescent, covered by simple and malpighiaceous trichomes, stellate trichomes absent, margin entire; inflorescence with 2, rarely 3, pistillate flowers, 11-25 staminate flowers, floral nectaries glabrous in both staminate and pistillate flowers; staminate flowers with 3-lobed petals, stamens 5, pistillate flowers with petals, styles glabrous, ovary and fruit covered by simple and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum argentinense is endemic to the northern region of Argentina and the Chaco province. It occurs in native forests of the Chaco, near the Andes, at elevations between 300-1000 meters, where it is associated with shaded environments.

Flowering and fruiting: Flowers and fruits can be found all year round, most frequently from October to January.

Notes: Skottsberg (1949Skottsberg C. 1949. Una especie nueva del género Chiropetalum Adr. Juss. de la República Argentina. Lilloa 17: 303-309.) did not consider that Grisebach (1874Grisebach AHR. 1874. Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen. Göttingen, German .) validly described the variety, so the author describes C. argentinense as a new species, without raising the variety to the species rank. Here, following art. 32.1 of the ICN (Turland et al. 2018Turland NJ, Wiersema JH, Barrie FR et al. 2018. International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code). Regnum Vegetabile 159. Glashütten, Koeltz Botanical Books.), the taxa proposed by Grisebach (1874) is validly published, but it has no priority over C. argentinense, because it is in another rank (art. 11.2 of the ICN).

Grisebach (1874Grisebach AHR. 1874. Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen. Göttingen, German .) described C. tricuspidatum var. angustifolium Griseb. based on two specimens (syntypes) present in its own herbarium, mentioning the shape and measures of the leaves and the type locality (Cordoba), without mentioning a single type. However, in the introduction to the work, the author mentions that the study is also based on Lorentz collections. Currently, Grisebach’s private collection is incorporated into the GOET herbarium (Stafleu & Cowan 1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.). Analyzing the two specimens used by the author in the description of the name, we designated P.G. Lorentz 77 (GOET006402) as the lectotype by the set of information present in the exsiccate.

Selected specimens examined: ARGENTINA. CHACO: Güemes, San Lorenzo, 12 Apr 1972, (fl. fr.), A.G. Schulz 18137 (SI). CÓRDOBA: Capital, Parque Sarmiento em bosque nativo, 09 Oct 2012, (fl. fr.), L.M. Carbone 736 (ACOR). LA RIOJA: Chilecito, Nonogasta, 900 m, 27 Dec 1928, S. Venturi 7830 (US). SALTA: San Luis del Palmar, Potrero del Funes, 10 Feb 1925, (fl. fr.), A. Castellano s.n. (BA). SAN LUIS: La Aguada, 5 Nov 1940, (fl. fr.), A. Burkart 10948 (SI).

25. Chiropetalum berterianum Schltdl., Linnaea 26: 637. 1853 [1855].

Description: Herb; leaves ovate, base obtuse to subcordate, pubescent, covered by simple and malpighiaceous trichomes, stellate trichomes absent, margin entire; inflorescence with 0-1 basal pistillate flowers, 10-40 distal staminate flowers; floral nectaries glabrous or pubescent in both staminate and pistillate flowers; staminate flower with 5-lobed petals, stamens 5; pistillate flowers with petals 0-4, linear, styles glabrous, ovary and fruit covered by malpighiaceous trichomes.

Key to the varieties of Chiropetalum berterianum

1. Floral nectaries pubescent 25a. Chiropetalum berterianum var.berterianum

1’. Floral nectaries glabrous 25b. Chiropetalum berterianum var.psiladenium

25a. Chiropetalum berterianum var. berterianum Schltdl., Linnaea 26: 637. 1853 [1855]. Argythamnia berteriana (Schltdl.) Müll.Arg. Linnaea 34: 151. 1865. Type: CHILE. In sylvis umbrosis collin, Quillota, Oct 1829, C.G. Bertero 226 (holotype: HAL [HAL0043498]!, isotypes: A [A00257844]!, G [G00434173]!, G [G00434174]!, G [G00434175]!, GH [GH00045758]!, GH [GH00257845]!, MO [MO2235041]!, P [P00634965]!).

Distribution and habitat: Chiropetalum berterianum var. berterianum is endemic to the western side of the Andes, from northern to central Chile (Fig. 5 A ). It occurs in open arid vegetation in the northern part of the country, classified as the Atacama province (Morrone 2014Morrone JJ. 2014. Cladistic biogeography of the Neotropical region: Identifying the main events in the diversification of the terrestrial biota. Cladistics 30: 202-214.), and in the central region called Desert Mesochilen, Central Chile and Valdivian provinces sense Rivas-Martínez & Navarro (1994Rivas-Martínez S, Navarro G. 1994. Mapa biogeográfico de Suramérica. Madrid, Published by the authors.), since Morrone (2014Morrone JJ. 2014. Cladistic biogeography of the Neotropical region: Identifying the main events in the diversification of the terrestrial biota. Cladistics 30: 202-214.) did not propose a classification for this region.

Flowering and fruiting: Flowers and fruits can be found from May to December.

Notes: The single diagnostic character of C. berterianum varieties is the presence or absence trichomes on floral nectaries, which are stable between varieties.

Selected specimens examined: CHILE. LOS ANDES: Santa Rosa de Los Andes, May 1882, (fl.), J. Ball 104 (NY). RANCAGUA: Termas de Cauquenes, S of Rio Cachapoal, ca 12 km E of Hwy, 600 m, 6 Oct 1993, (fl. fr.), L.R. Landrum 7898 (MBM). SANTIAGO: Cerro Culibrin, Oct 1950, (fl.), F. Gallardo 274 (NY). VALPARAISO: Valdivia, Casilla 22, 18 Nov 1895, (fl. fr.), O. Buchtien s.n. (US).

25b. Chiropetalum berterianum var. psiladenium Skottsb. Acta Horti Gothoburgensis 18: 63. 1949. Argythamnia berteroana var. psiladenia (Skottsb.) Ingram. Gentes Herbarum; 11: 454. 1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468. Type: CHILE. VALPARAISO: Quintero, 20 m, Sep 1923, E. Werdermann 34 (holotype: S [S-R-10596]!, isotypes: BM [BM000947430]!, CAS [CAS0001961]!, E [E00273096]!, F [F0055982F]!, G [G00434172]!, GH [GH00045759]!, NY [NY03932673]!, US [US00109825]!).

Distribution and habitat: Chiropetalum berterianum var. psiladenium is endemic to the western side of the Andes in central Chile, classified as Central Chilean and Valdivian provinces (Rivas-Martínez & Navarro 1994Rivas-Martínez S, Navarro G. 1994. Mapa biogeográfico de Suramérica. Madrid, Published by the authors.), and it occurs in open arid vegetations (Fig. 5 C ).

Flowering and fruiting: Flowers and fruits can be found from September to December.

Selected specimens examined: CHILE. COQUIMBO: La Serena, Oct 1926, (fl., fr.), C. Joseph 4419 (US). Deserto do Atacama, 1885, (fl.), W. Geisse 48 (NY).

26. Chiropetalum boliviense (Müll.Arg.) Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 94. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia boliviensis Müll.Arg. Linnaea 34: 149. 1865. Type: BOLIVIA. LARECAJA: Vinicitis Sorata, Cerro del Iminapi, 2650 m, 1859-1860, G. Mandon 1081 (lectotype [first-step] inadvertently designated by Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468, [second-step] designated here: G-DC [G00313503]! (specimen at the right on a sheet with two specimens, each having its barcode), isolectotypes: A [A00045761]!, BM [BM000947428]!, BR [BR0000006999421]!, F [F0055884F]!, G [G00434170]!, G-DC [G00313502]!, G-DC [G00313504]!, GH [GH00045760]!, GOET [GOET003317]!, K [K000600297]!, MPU [MPU014921]!, MPU [MPU014922]!, NY [NY00246255]!, NY [NY00246256]!, P [P00634967]!, P [P00634968]!, P [P00634969]!, S-R [S-R-10600]!).

= Chiropetalum triandrum Griseb. Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen 24: 56. 1879. Argythamnia triandra (Griseb.) Allem & Irgang, Revista Brasileira de Biologia 36: 286. 1976Allem AC, Irgang BE. 1976. Two new species of Argythamnia (Euphorbiaceae) from Rio Grande do Sul, Brazil. Revista Brasileira de Biologia 36: 283-287.. Type: ARGENTINA. CATAMARCA: na Hecken in Fuerte de Andagala, Mar 1875, F. Schickendantz 231 (lectotype designated by Ingram 1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468b: GOET [GOET006395]!, isolectotypes: CORD [CORD00005964]!, G [G00434171]!). Remaining syntypes: ARGENTINA. TUCUMAN: Siambon. G. Hieronymus & P.G. Lorentz 769: CORD [CORD00005962]!, GOET [GOET006394]!, Berlin Negative F [F0BN005243]!; P.G. Lorentz & G. Hieronymus 1040: CORD [CORD00005963]!, GOET [GOET006394]!.

Description: Herb to subshrub; leaves ovate, base rounded to acute, covered by simple, stellate and malpighiaceous trichomes, margin serrate, teeth 20-32 per side; inflorescence with 1-4 pistillate basal flowers, 11-25 distal staminate flowers, floral nectaries pubescent in both staminate and pistillate flowers; staminate flower with petals 5(6)-lobed, stamens 3(4-5), pistillate flowers without petals, styles glabrous, ovary and fruit covered by simple and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum boliviense is distributed in northern Argentina and central and southern Bolivia (Fig. 5 C ), at elevations of 500-3100 meters. It occurs in the interior of the most humid forests of the northern Chaco and southern Rondônia provinces.

Flowering and fruiting: Flowers and fruits can be found throughout the year, most frequently between September and January.

Notes: When Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) described C. boliviense, he did not indicate a type specimen, and there were four specimens (mounted on three sheets) in the G herbarium, where he worked. Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) considered the specimens deposited in G-DC as the holotype, but the author does not specify a specimen, indicating a lectotype [first-step] according to art. 9.17 of ICN (Turland et al. 2018Turland NJ, Wiersema JH, Barrie FR et al. 2018. International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code). Regnum Vegetabile 159. Glashütten, Koeltz Botanical Books.). By indicating the specimens as a holotype, Ingram (1980bIngram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) also is making an “inadvertent lectotypification” for using the term holotype for a syntype. This inadvertent lectotypification is acceptable according to art. 9.23 ICN when published before 1 January 2001. According to art. 9.10 ICN, the use of the term “holotype” should be treated as an error to be corrected. So, here we indicate the lectotype [second-step] G. Mandon 1081 deposited in G-DC (G00313503). This specimen is mounted on the right of a sheet with another specimen, both having their respective barcodes. This specimen was chosen because it was on a sheet with the original label of Mandon and deposited in the collection where the author of the species worked. We also analyzed the protologue and the type specimens of C. triandrum and agreed with Ingram (1980b) that this name is a synonym for C. boliviense.

Selected specimens examined: ARGENTINA. CATAMARCA: Andalgala, 04 Oct 1915, (fl. fr.), P. Jorgensen 1059 (BA, SI, US). CHACO: Sargento Cabral, Parque Nacional Chaco, alredores del Río Negro, 22 Nov 1991, (fl. fr.), R.H. Fortunato et al. 2564 (SI). JUJUY: Ladesma, Sierra de Calilegua, 12 Sep 1927, (fl.), S. Venturi 5804 (SI, US). SALTA: Oran, El Cedral, 26 Oct 1913, (fl. fr.), Rodriguez 1061 (BA, NY, SI). TUCUMAN: Tafi, Yerba Buena, 900 m, 10 Apr 1920, (fl.fr.), S. Venturi 843 (BA, NY, SI, US). BOLIVIA. ACRE: Bermejo, Tarija, 1900 m, 6 Dec 1903, (fl. fr.), K. Fiebrig 2338 (NY, SI). LA PAZ: Bautista Saavedra, 1500 m, 19 Apr 2005, (fl. fr.), A. Fuentes et al. 6978 (NY). SANTA CRUZ: Florida, 2200 m, 2 Jun 1991, (fl.), M. Nee 40679 (NY).

27. Chiropetalum canescens Phil., Florula Atacamensis seu Enumeriatio 49. 1860. Argythamnia canescens (Phil.) F.Phil. Anales de la Universidad de Chile 262. 1881. Type: CHILE. ANTOFAGASTA: Prope Hueso Parado, 1200 m, R. Philippi s.n. (holotype: SGO [SGO000002992]!, isotype: BH fragment [indicated by Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468, not seen here]).

=Chiropetalum sponiella (Müll.Arg.) Pax, Die Natürlichen Pflanzenfamilien 3(5): 45. 1890. Argythamnia sponiella Müll.Arg. Linnaea 34: 148. 1865. Type: CHILE. Cobija, C. Gaudichaud s.n. (lectotype designated by Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468: G-DC [G00313508]!).

=Chiropetalum gigouxii Espinoza, Revista Chilena de Historia Natural 40: 190. 1936[1937]. Type: CHILE. Atacama. Caldeira, E. Gigoux s.n. (holotype: SGO [SGO151550]!).

Description: Herb; leaves lanceolate to elliptic, base rounded to cuneate, pubescent, covered by simple and malpighiaceous trichomes, stellate trichomes absent, margin entire; inflorescence with 1 basal pistillate flower, 8-13 distal staminate flowers, floral nectaries glabrous in both staminate and pistillate flowers, staminate flower with 4-5-lobed petals, stamens 5, pistillate flowers without petals, styles glabrous, ovary and fruit covered by simple and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum canescens is endemic to the northern region of Chile, called by Morrone (2014Morrone JJ. 2014. Cladistic biogeography of the Neotropical region: Identifying the main events in the diversification of the terrestrial biota. Cladistics 30: 202-214.) as the Atacama province, where it occurs in arid vegetation below 500 meters elevation (Fig. 5 B ).

Flowering and fruiting: Flowers and fruits can be found between September and December.

Notes: In the protologue of Argythamnia sponiella, Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) mentions as type the specimen C. Gaudichaud s.n., with the collection site Cobija, Bolivia. However, this species does not occur in this country, since it is endemic to the west coast of the Andes. Nevertheless, at the time of the Gaudichaud`s trip, Bolivian territory extended to the Pacific coast, where the specimen was collected, which currently comprises the city of Antofagasta, in Chile (Lofstrom 1974Lofstrom W. 1974. Cobija, Bolivia’s First Outlet to the Sea. The Americas 31: 185-205.).

Selected specimens examined: CHILE. ANTOFAGASTA: Taltal, 300 m, Oct 1925, (fl.), E. Werdermann 773 (NY, SI, US). Atacama: Puerto de Chañaral, 28-29 Oct 1925, (fl.), I.M. Johnston 4780 (BA, US).

28. Chiropetalum cremnophilum I.M.Johnst., Contributions from the Gray Herbarium of Harvard University 85: 64. 1929. Argythamnia cremnophila (I.M.Johnst.) J.W.Ingram, Gentes Herbarum: Occasional Papers on the Kinds of Plants 11: 449. 1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468. Type: CHILE. ANTOFAGASTA: Taltal, about head of fog-bathed sea cliffs near Aguada Grande, 16-18 Dec 1925, I.M. Johnston 5779 (holotype: GH [GH00045762]!).

Description: Herb; leaves cordate to ovate, base rounded to cordate, pubescent, covered by simple and malpighiaceous trichomes, stellate trichomes absent, margin entire; inflorescence with 1 basal pistillate flower, 3-7 distal staminate flowers, floral nectaries glabrous in both staminate and pistillate flowers, staminate flowers with 3-4-lobed petals, stamens 5, pistillate flowers without petals, styles glabrous, ovary and fruit covered by simple and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum cremnophilum is endemic to the western slope of northern Chile (Fig. 5 B ). It occurs in arid formations of the Atacama province, as defined by Morrone (2014Morrone JJ. 2014. Cladistic biogeography of the Neotropical region: Identifying the main events in the diversification of the terrestrial biota. Cladistics 30: 202-214.).

Flowering and fruiting: Flowers and fruits can be found between September and February.

Selected specimens examined: CHILE. ANTOFAGASTA: Taltal, 14-15 Dec 1925, (fl.), I.M. Johnston 5705 (BA, US). Campanha, 28 Feb 1954, (fl.fr.), A. Garaventa 4141 (SI).

29. Chiropetalum foliosum (Müll.Arg.) Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 91. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia foliosa Müll.Arg., Linnaea 34: 150. 1865. Type: In Brasilia Meridionalis [BRAZIL. RIO GRANDE DO SUL]: F. Sellow s.n. (lectotype designated by Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468: G [G00434168]!), isolectotype: P [indicated by Ingram 1980b, not seen here]).

Description: Herb; leaves ovate, base rounded, pubescent, covered by long, simple and malpighiaceous trichomes, stellate trichomes absent, margin serrate, 5-8 teeth; inflorescence with 1, rare 2, basal pistillate flowers, 2-5 distal staminate flowers, floral nectaries glabrous in both staminate and pistillate flowers, staminate flower with 3-lobed petals, stamens 5, pistillate flowers without petals, styles glabrous, ovary and fruit covered by simple and malpighiaceous trichomes.

Distribution and habitat: The species occurs in Brazil and Uruguay (Fig. 5 B ) in the Pampas phytogeographical domain, in rocky grassland covered by herbaceous and shrub vegetation.

Flowering and fruiting: Flowers and fruits can be found from July to April.

Notes: The species was previously known from two collections, the type material, Sellow s.n. from Brasilia Meridionalis (no specific location), and M. Sobral 3571 from Viamão, Rio Grande do Sul, Brazil. During this study a specimen from Rivera, Uruguay, was found in herbarium collections, and four new collections were recorded in the municipality of Porto Alegre and Piratini during field expeditions. Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) designated the specimen deposited in G (G00434168) as the lectotype and the author also mentioned that he saw a specimen in the herbarium P, but we did not have access to this material during our study.

Selected specimens examined: BRAZIL. RIO GRANDE DO SUL: Piratini, Quinto distrito, 31°36’28”S, 53°09’11”W, 6 Sep 2023 (fl.), J. Külkamp et al. 1584 (FLOR, PEL, RB). Porto Alegre, Morro da Tapera, borda da trilha na face leste do morro, 30°08’09.2”S, 51°11’15.7”W, 15 Jul 2017 (fl. fr.), J. Külkamp et al. 230 (ICN, RB). Viamão, Parque Estadual de Itapuã, em campo pedregoso na encosta de um morro, 02 Dec 1984, (fl. fr.), M. Sobral 3571 (MBM). URUGUAY. RIVERA: Ruta 29, km 15, Cerro Chato Dorado, Laderas de cerro, 31°03’59”S, 55°27’27”W, 12 Dec 1997 (fl. fr.), E. Marchesi et I. Grela s.n. (MVFA 27163).

30. Chiropetalum griseum Griseb., Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen 24: 57. 1879. Argythamnia grisea (Griseb.) Allem & Irgang, Revista Brasileira de Biologia 36: 286. 1976Allem AC, Irgang BE. 1976. Two new species of Argythamnia (Euphorbiaceae) from Rio Grande do Sul, Brazil. Revista Brasileira de Biologia 36: 283-287.. Type: ARGENTINA. CORDOBA: G. Hieronymus 92 (lectotype, designated by Ingram 1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468b: GOET [GOET003318]!, isolectotypes: CORD [CORD00005965]!, F [F0055984F]!, G [G00434167]!). Remaining syntype: ARGENTINA. CORDOBA: G. Hieronymus 112 (F [F0055984F]!, GOET [GOET006404]!).

=Chiropetalum cupreumPax & K. Hoffm., Pflanzenr. IV 147 VI 57: 89. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Type. PARAGUAY. GRAN CHACO: Loma Clavel, E. Hassler 2497 (lectotype first-step designated by Ingram 1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468b, second-step designated here: G [G00307039]!, isolectotypes: G [G00307036]!, GH [GH00045763]!, NY [NY00246360], P [P00634974]!, S [S-R-10598]!, K [K000600301]!, K [K000600300]!, Negative of destroyed holotype in Berlin F [F0BN005238]!.

Description: Herb to subshrub; leaves ovate, base rounded, covered by simple, stellate and malpighiaceous trichomes, margin serrate, 5-11 teeth per side; inflorescence with 1-2 basal pistillate flowers, 4-12 distal staminate flowers, floral nectaries pubescent in both staminate and pistillate flowers; staminate flower with 3-5-lobed petals, stamens (4)5, pistillate flowers with petals absent, glabrous styles, ovary and fruit densely covered by stellate trichomes, in addition to simple and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum griseum is distributed in Argentina, Paraguay, and Uruguay (Fig. 5 A ), occurring in vegetation of dry and gallery forests of the Chaco and Pampa provinces.

Flowering and fruiting: Flowers and fruits can be found all months of the year.

Notes: In the introduction, Grisebach (1879Grisebach AHR. 1879. Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen. Göttingen, German .) mentions that the study was based on collections made by Hieronymus, Lorentz, and Schickendantz. In the GOET herbarium, where the private collection of Grisebach is included (Stafleu & Cowan 1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.), there are two gatherings of C. griseum from Argentina, G. Hieronymus 92 and G. Hieronymus 112. Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) treats the specimen Hieronymus 92 (GOET003318) as a holotype, according to art. 9.10 ICN, the use of the term “holotype” should be treated as an error to be corrected for lectotype. We agreed with Ingram (1980b). The gathering G. Hieronymus 112 (F0055984F, GOET006404) is the remaining syntype.

Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) designates the specimen E. Hassler 2497 (G) as the lectotype of C. cupreum. However, we found two specimens in the collection (G00307036, G00307039). Here we perform the second-step lectotypification, and selected G00307039 as the lectotype of C. cupreum.

Selected specimens examined: ARGENTINA. BUENOS AIRES: San Isidro, 23 Oct 1933, (fl. fr.), L.R. Parodi 11301 (BAA, SI, US). Cordoba: Capital, 27 Dec 1935, (fl.), A. Burkart 7298 (SI). CORRIENTES: San Luis del Palmar, Oct 1976, (fl. fr.), A. Schinini et C.L. Cristobal 13680 (MBM, SI). ENTRE RIOS: Paraná, 32 km al norte de Paraná, Oct 1962, (fl. fr.), A. Burkart 23719 (MBM). PARAGUAY. GRAN CHACO: Loma Clavel, Nov 1903, (fl. fr.), E. Hassler 2497(NY).

31. Chiropetalum intermedium Pax & K.Hoffm. Pflanzenr. IV.147.vi (Heft 57), 91. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia intermedia (Pax & K.Hoffm.) Allem & Irgang, Rev. Bras. Biol. 36: 286. 1976Allem AC, Irgang BE. 1976. Two new species of Argythamnia (Euphorbiaceae) from Rio Grande do Sul, Brazil. Revista Brasileira de Biologia 36: 283-287.. Type: Südbrasilianische Provinz [URUGUAY], Campos, J. Arechavaleta 37 (holotype: B destroyed), neotype designated here: URUGUAY. Orillas del Río, October 1890, J. Arechavaleta s.n. (MVM-5263!).

Description: Herb to subshrub; leaves elliptic to ovate, base rounded, covered by malpighiaceous rarely stellate trichomes, margin serrate, 12-19 teeth per side; inflorescence with 1-3 basal pistillate flowers and 2-7 distal staminate flowers, floral nectaries glabrous in both staminate and pistillate flowers; staminate flower with (3)5-lobed petals, stamens 3-4, pistillate flowers lacking petals, pubescent style, ovary and fruit covered by malpighiaceous trichomes, stellate trichomes absent.

Distribution and habitat: Chiropetalum intermedium is distributed in Brazil and Uruguay. In Brazil, it occurs in central and southern portion of the state of Rio Grande do Sul (Fig. 5 A ). It occurs in the Pampa province, in the understory of open forest, grasslands associated with rocky outcrops, and along the edges of riparian forests.

Flowering and fruiting: Flowers and fruits can be found throughout the year, but more often from September to February.

Notes: Chiropetalum intermedium was cited for Uruguay and Argentina (Pax & Hoffmann 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142., Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468), but after reviewing herbaria collections we found that some specimens from Argentina were misidentified and they are C. griseum. For this reason, we exclude the occurrence of C. intermedium for Argentina and confirm its occurrence for Brazil (new records) and Uruguay.

The type material of C. intermedium deposited in the Berlin Herbarium was destroyed during World War II (Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468). In the taxonomic revision for the genus, Ingram (1980b) indicated the possibility of having an isotype in the MVM herbarium. However, no specimens were found during the revision of this herbarium. Therefore, according to the Art. 9.16 of the ICN we choose a neotype for C. intermedium. The specimen was designated based on the collector and the original location of the type, which was also collected by J. Arechavaleta in grasslands from Uruguay.

Selected specimens examined: BRAZIL. RIO GRANDE DO SUL: Arroio Grande, 02 Nov 1961 (fl. fr.), G. Pabst et E. Pereira 6724 (HB, RB); Caçapava do Sul, Guaritas, 26 Sep 1985 (fl. fr.), D.B. Falkenberg 2662 (FLOR); 50 metros da escada de acesso ao topo da Pedra do Leão, 30°32’47”S, 53°33’13”W, 18 Sep 2016 (fl. fr.), J. Külkamp et C. Rabuske 81 (ICN); Santana da Boa Vista, Pedra da Cruz, 30°53’48”S, 53°25’25.3”W, 03 Dec 2016 (fl. fr.), J. Külkamp et al. 154 (ICN); Pedra da Cruz, 30°53’48”S, 53°25’25.3”W, 03 Dec 2016 (fl, fr), J. Külkamp et al. 155 (ICN). URUGUAY. ARTIGAS: San Gregorio, Costa del Rio Uruguay, Campos de arrocera Riusa, unos 2 km al Oeste de confluencia de Cañada Yacaré y A Tigre, 30°34’27.60”S, 57°50’16.7”W, 28 Sep 2014 (fl. fr.), Rossado et F. Haretche 801 (MVJB); CANELONES: 15 Nov 1908 (fl. fr.), M.B. Berro 542 (MVM); Santa Lucía, en el monte, terreno arenoso, Dec 1874 (fl. fr.), Arechavaleta 3552 (MVM); SAN PEDRO DEL TIMOTE: Arroyo Mansa Villagra, en bosque ribereño, 02 Oct 1942 (fl. fr.), PE 5021 (MVM).

32. Chiropetalum latifolium (Chodat & Hassl.) Külkamp & Iganci, stat. nov.

Basionym: Chiropetalum tricoccum (Vell.) Chodat & Hassl. f. latifolia Chodat & Hassl., Bull. Herb. Boissier, 2(5): 502. 1905Chodat RH, Hassler E. 1905. Chiropetalum. In: Durand E, Barratte G (eds.). Florae Lybicae Prodromus ou Catalogue Raisonne des Plantes de Tripolitaine. Bulletin de L’Herbier Boissier 2: 501-502.. Type: PARAGUAY. CENTRAL: Ad ripam lacus Ypacaray, Feb 1898-1899, E. Hassler 3927 (lectotype designated here: G [G00307035]!, isolectotypes: A [A00045924]!, BM [BM000504338]!, G [G00307030]!, G [G00307032]!, G [G00307033]!, G [G00307034]!, K [K000600299]!, MPU [MPU014910]!, NY [NY00246361]!, P [P00634980]!, UC [UC941597]!).

Description: Subshrub; leaves ovate to lanceolate, base rounded, covered by malpighiaceous trichomes, stellate trichomes absent, margin serrate, 12-25 teeth per side; inflorescence with 1-4 basal pistillate flowers and 12-28 distal staminate flowers, floral nectaries pubescent in both staminate and pistillate flowers, staminate flower with 4-7-lobed petals, stamens 5; pistillate flowers without petals, styles glabrous, ovary and fruit covered by malpighiaceous and simple trichomes.

Distribution and habitat: Chiropetalum latifolium is distributed in Argentina, Brazil, Paraguay and Uruguay (Fig. 5 B ). It occurs in the understory of open and riparian forest of the Chaco, Pampa, and Parana Forest provinces.

Flowering and fruiting: Flowers and fruits can be found throughout the year, but are more frequent from October to February.

Notes: When Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) assigned an physical specimen to Argythamnia tricocca (Vell.) Müll.Arg., a confusion began about these names, because this epitype from South Brazil and Vellozo’s illustration based on a specimen from Rio de Janeiro correspond to different species. Chodat & Hassler (1905Chodat RH, Hassler E. 1905. Chiropetalum. In: Durand E, Barratte G (eds.). Florae Lybicae Prodromus ou Catalogue Raisonne des Plantes de Tripolitaine. Bulletin de L’Herbier Boissier 2: 501-502.) describe the C. tricoccum f. latifolia based on the specimen E. Hassler 3927 from Paraguay, and they only mention the height of the plant and measurements of the leaves in the protologue. By studying the types and protologues, we conclude that the physical specimen attributed by Müller corresponds to the same entity C. tricoccum f. latifolia described by Chodat & Hassler (1905), and both differ from the species described by Vellozo. Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.) treat C. tricoccum f. latifolia as a synonym of C. tricoccum. As discussed in the comments of C. triccocum, we conclude that C. tricoccum f. latifolia is a distinct species, and here we elevate it to the rank of species as C. latifolium. In the protologue of f. latifolia Chodat & Hassler (1905) do not indicate the herbarium where the type was deposited, so according to the Art. 9.11 of the ICN, here we are designate E. Hassler 3927 (G00307035) as lectotype of C. latifolium. Chiropetalum latifolium has a more southern distribution than C. tricoccum (Fig. 5 A -B).

Selected specimens examined: ARGENTINA. CORRIENTES: Capital, En baldío. Sotobosque, 01 May 1989 (fl. fr.), A. Krapovickas et C.L. Cristóbal 15380 (MBM). Concepcion: Estancia San Justo del Palmar, 10 Nov 1982 (fl. fr.), T.M. Pedersen 13446 (MBM, NY). BRAZIL. MATO GROSSO DO SUL: Bela Vista, Rod. MS-384, Rio Guaviral, 10 Nov 1993 (fl. fr.), G. Hatschbach et al. 58833 (MBM). Paraná: Campo Mourão, Rio da Vargem, 10 Dec 1960 (fl. fr.), G. Hatschbach 7554 (MBM). RIO GRANDE DO SUL: Derrubadas, Parque Estadual do Turvo, estrada Porto Garcia, 27°08’11”S 53°52’18”W, 03 Jul 2009 (fl. fr.), G.A. Dettke 384 (ICN); Estrela, Barranco do Rio Taquari, May 2017 (fl. fr.), J. Külkamp et al. 225 (ICN, RB). PARAGUAY. Departamento Acahay Massif: Eastern most Peak, 20 Jan 1992 (fl. fr.), E. Zardini et R. Franco 29849 (UPCB). Paraguari, on diorite rock outcrops on eastern side of eastern peak, 21 Jul 1988 (fl. fr.), E. Zardini et R. Franco 5843 (UPCB); URUGUAY. Salto, 12 Spt 1961, (fl.), D. Puerto 31 (MVFA). Paysandú: Paso Andrés Perez, Queguay Grande, 05 Apr 2008, (fl. fr.), F. Haretche 106 (MVJB).

33. Chiropetalum molle (Müll.Arg.) Pax & K.Hoffm. Pflanzenr. IV.147.vi (Heft 57) 92, 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia mollis Müll.Arg., Adansonia 4: 289. 1864. Type: In Brasilia Meridionalis [BRAZIL. RIO GRANDE DO SUL]: F. Sellow s.n. (lectotype [first-step] designated by Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468, [second-step] designated here: G [G00415056]!, isolectotypes: BR [BR0000006998776]!, F [F336638] [fragment]!, F [F336651] [fragment]!, F [F336652]!, [G00415057]!, [G00415058]!, K [K000600302]!, P [P00634975]!, P [P04865053]! - (specimen of Sellow numbered by Gaudichaud [Gaudichaud 1691]), TUB [TUB009144]!).

= Chiropetalum pilosistylum (Allem & Irgang) Radcl.-Sm. & Govaerts, Kew Bull. 52: 478. 1997. Argythamnia pilosistyla Allem & Irgang, Rev. Bras. Biol. 36: 285. 1976. Type: BRAZIL. RIO GRANDE DO SUL: Cambará do Sul, in Araucária forest, near the river, February 1948, Rambo s.n. (holotype: PACA36212!, isotypes: BH, S [both isotypes were cited in the protologue; however, we have not seen them in this study]). syn. nov.

Description: Subshrub to shrub; leaves lanceolate to elliptic, base obtuse, adaxial surface irregular, both surfaces covered by simple, stellate and malpighiaceous trichomes, margin biserrate, 14-40 teeth per side; 1-3 inflorescences per node, 1-4 basal pistillate flowers and 11-34 distal staminate flowers, floral nectaries glabrous on both staminate and pistillate flowers, staminate flowers with 5-7-lobed petals, stamens 5(6); pistillate flowers lacking petals, styles pubescent in the basal half and glabrous in apical half, ovary and fruit covered by simple, stellate, and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum molle is distributed in southern Brazil and Uruguay (Fig. 5 C ), in the understory of open forest and grasslands associated with rocky outcrops, between 100-1400 meters elevation, in the Pampa and Araucaria Forest provinces.

Flowering and fruiting: Flowers and fruits can be found from September to April.

Notes: Controversies over the authorship of C. molle have caused confusion among taxonomists. Chiropetalum molle Klotzsch was indicated as a new species for Brazil, but no description nor a type specimen were presented (Klotzsch 1841). Baillon (1864Baillon HE. 1864. D’Observations Botaniques. Adansonia 4: 1-289.) transferred C. molle to Argythamnia, establishing A. mollis and citing three specimens examined “(- Sellow, Brésil herb. Mus., ex herb, Berl. - A. S. H., cat. C2, n. 2049, Banda oriental del Uruguay, un pelit bois près de S. Thereza (dioique). - Gaudichaud, Herb. imp. brés., n. 1691, Prov. de Rio Grande do Sul).” However, no description or diaganosis was provided by Baillon, it being a nomen nudum as well. Later, Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) provided a description for A. mollis, based on the specimen Sellow s.n. (in hb. Berol.), one of the specimens cited by Baillon (1864). In this same study, Müller makes reference to C. molle Klotzsch as a nomem. Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.) accepted C. molle Klotzsch, but later, Ingram (1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468b) used the name A. mollis Müll.Arg for this species.

The names of Baillon (1864Baillon HE. 1864. D’Observations Botaniques. Adansonia 4: 1-289.) and Klotzsch (1841Klotzsch JF. 1841. Neue und weniger gekannte siidamerikanische Euphorbiaceen - Gattungen. Archiv für Naturgeschichte 7-1: 175-204.) have not been validly published. Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) was the first author to validly describe the species. As it was combined for Chiropetalum by Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.), the correct name in Chiropetalum should be C. molle (Müll.Arg.) Pax & K.Hoffm.

Another incongruence related to this species was the lectotypification performed by Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468), who while designating a lectotype (Sellow s.n.) for A. mollis, cited the herbarium G as the repository. However, this herbarium has three duplicates, and the author does not specify this. The author indicates a lectotype first-step, thus, according to Art. 9.17 of the ICN (Turland et al. 2018Turland NJ, Wiersema JH, Barrie FR et al. 2018. International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code). Regnum Vegetabile 159. Glashütten, Koeltz Botanical Books.), here we designate Sellow s.n. G (G00415056) as the second-step lectotype of C. molle. This specimen was chosen because it is more complete and because it has an original label from the Berlin herbarium, the institution where the author of the species worked. According to Moraes (2023Moraes PLR. 2023. Redux Sellow: revealing Sellow’s collections from the Herbier Impérial du Brésil at the Paris Herbarium. Phytotaxa 596: 1-216. doi: 10.11646/phytotaxa.596.1.1
https://doi.org/10.11646/phytotaxa.596.1... ), Gaudichaud did not collect in southern Brazil, and the specimens attributed to him were in fact collected by Sellow. During the passage through Rio de Janeiro, several specimens of Sellow were donated to Gaudichaud, who numbered them as his collections. The specimens cited in the protologue of C. molle “Gaudichaud, Herb. imp. brés., n. 1691, Prov. de Rio Grande do Sul” should be considered as isolectotypes, as they belong to the Sellow s.n. collection. We found the specimen (P04865053) numbered by Gaudichaud, which is Sellow s.n. and consequently, isolectotypes of C. molle.

After studying protologues, type specimens, field collect, and herbarium specimens, we concluded that Chiropetalum pilosistylum is synonym of C. molle. Allem & Irgang (1976Allem AC, Irgang BE. 1976. Two new species of Argythamnia (Euphorbiaceae) from Rio Grande do Sul, Brazil. Revista Brasileira de Biologia 36: 283-287.) described C. pilosistylum but did not mention the relationship of this species with C. molle in the protologue. Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) accepts both species, probably because he had few specimens to make such a decision. In the protologue, the authors cite an isotype of C. pilosistylum for the BH herbarium and Ingram (1980bIngram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) cites another for S, but neither these specimens were found by us.

Selected specimens examined: BRAZIL. RIO GRANDE DO SUL: Bagé, Casa de Pedra, 30°57’37.65”S, 53°35’26.26”W, 10 Oct 2017 (fl. fr.), J. Külkamp et al. 334 (ICN). Montenegro, Pareci, Linha Bonita perto de Montenegro ad rio em Silva, 19 Jan 1949 (fl. fr.), B. Rambo 39986 (PACA). Trindade do Sul, Projeto de Assentamento Trindade, em beira de floresta ciliar do Lageado Passo do Cervo, 15 Sep 2008 (fl. fr.), M. Grings 718 (ICN); Veranópolis, Paredão de basalto a 10 km S de Veranópolis, 16 Sep 1971 (fl. fr.), J.C. Lindeman et B.E. Irgang s.n. (ICN008106). SANTA CATARINA: Bom Retiro, Campo dos Padres, 23 Jan 1957 (fl. fr.), B. Rambo 60191 (PACA); Urubici, Vacas Gordas, Parque Nacional de São Joaquim, 1,5 km do alojamento do parque (pistillated specimen), 28°08’57.9” S, 49°37’524” W, 11 Dec 2016 (fl. fr.), J. Külkamp et al. 190 (ICN). Urupema, Morro das torres, ao lado da cachoeira que congela (pistillated specimen), 27°55’40.9”S, 49°51’18.6”W, 1532 m, 12 Dec 2016 (fl. fr.), J. Külkamp et al. 207 (ICN). URUGUAY. RIVERA: Rivera, 30°55’48”S, 55°39’15.5”W, 10 Oct 2022, A. González et J.L. Antúnez s.n. (MVM23504).

34. Chiropetalum patagonicum (Speg.) O’Donell & Lourteig, Lilloa 8: 41. 1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. . Aonikena patagonica Speg. Anales del Museo Nacional de Buenos Aires 7: 162. 1902. Type: ARGENTINA. Chonkenk-aik, Río chico, in campis sabulosis editioribus secus, Feb 1898, (fl. fr.), C. Ameghino s.n. (holotype: LP [LP003172]!).

Description: Annual herb; leaves orbicular, ovate or cordate, base cordate to rounded, glabrous, margin entire to crenate with 1-4 teeth per side; inflorescence with 1-3 basal pistillate flowers and 3-5 distal staminate flowers, floral nectaries glabrous on both staminate and pistillate flowers, petals of the staminate flowers entire with an undulate apex, stamens 3(-5), pistillate flowers without petals, styles glabrous, ovary and fruit glabrous.

Distribution and habitat: Chiropetalum patagonicum is endemic to Argentina and occurs the southern half of the country, with the majority of the scarce records from the Patagonia region (Fig. 5 C ). It is distributed in open arid environments, mainly in sand along the margins of the temporary rivers, between 200-750 meters above sea level in the Monte and Patagonia provinces.

Flowering and fruiting: Flowers and fruits can be found from September to February.

Notes: Due to some unique morphological characteristics, such as an annual life cycle, absence of trichomes, and petals entire to 3-lobed, C. patagonicum was first described as a monospecific genus and its circumscription has been questioned by some researchers (O’Donell & Lourteig 1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ; Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468). Ingram (1980b), for example, treats the taxon in the genus Aonikena Speg. whereas O’Donell & Lourteig (1942O’Donell CA, Lourteig A. 1942. Chrozophorae Argentinae. Lilloa 8: 37-81. ) circumscribes in Chiropetalum section Aonikena (Speg.) O’Donell & Lourt. Here we follow the classification of O’Donell & Lourteig (1942). However, we do not recognize sections. Külkamp et al. (2023 a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.) did not sample this taxon in the phylogenetic reconstruction, which is necessary in future studies to understand the position of this taxon in Ditaxeae.

Selected specimens examined: ARGENTINA. BUENOS AIRES: Bahia Blanca, 1884, (fl. fr.), M.G. Mansel r.n. (BM000552159). CÓRDOBA: La Cesira, Villa Maria, 25 Sep 1904, (fl. fr.), E.S. Holanbey 12820 (CORD). LA PAMPA: La Maruja, 11 Nov 1939, (fl. fr.) A. Burkart 9881 (SI, US). MENDONZA: San Rafael, RP190, puesto Los Pejecitos, 7 Dec 1973 (fl.), O. Boelcke et al. 15662 (SI). RIO NEGRO: General Roca e vicinity, 18 Oct 1914, (fl. fr.), W. Fischer 148 (F, NY, MO, SI, US). SAN LUIS: Villa Mercedes, 11 Nov 1940, (fl. fr.) A. Burkart 10881 (SI). SANTA CRUZ: Lago Buenos Aires, Ruta 40, 19 Feb 1970, (fl. fr.), E.G. Nicora 7537 (BAA); E.G. Nicora 7538 (BAA).

35. Chiropetalum pavonianum (Müll.Arg.) Pax, Die Natürlichen Pflanzenfamilien 3, 5: 45. 1890. Argythamnia pavoniana Müll.Arg., Linnaea 34: 149. 1865. Type: PERU. J.A.J. Pavon s.n. (holotype: G-DC [G005596]!).

Description: Subshrub to shrub; leaves elliptic to ovate, base acute to rounded, with simple, stellate and malpighiaceous trichomes, margin serrate, 10-16 teeth per side; inflorescence with 1-3 basal pistillate flowers and 6-13 distal staminate flowers, floral nectaries pubescent on both staminate and pistillate flowers, staminate flower with 5-lobed petals, stamens 5, pistillate flowers without petals, styles pubescent, ovary and fruit densely covered by malpighiaceous trichomes, in addition to simple trichomes, stellate trichomes absent.

Distribution and habitat: Chiropetalum pavonianum is endemic to Peru (Fig. 5 C ), where few records are known from the northern part of the country.

Flowering and fruiting: Flowers and fruits can be found from September to November.

Notes: The main collection of Ruiz & Pavon is in the MA herbarium, but no specimens were found. According to the herbarium technician (Eva García Ibáñez), Ruiz sold part of his collection to fund his botanical research. Thus, we consider the only specimen found in G-DC as a holotype of the name. Chiropetalum pavonianum is a poorly known species and apparently similar to C. ruizianum (Müll.Arg.) Pax & K.Hoffm. Further studies should be carried out to understand their relationships.

Selected specimens examined: PERU. BAGUA: Hacienda Marerilla on Río Utcubamba, 400 m, 01 Oct 1957, (fl. fr.), P.C. Hutchison 1510 (MO).

36. Chiropetalum phalacradenium (J.W.Ingram) L.B.Sm. & Downs, Fl. Ilustr. Catarin. (Euphorbiac.) 1: 155. 1988. Argythamnia phalacradenia J.W.Ingram, Gentes Herbarum, Occasional Papers on the Kinds of Plants 11: 458. 1980. Type: BRAZIL. SANTA CATARINA: Lauro Müller, rain forest, lower and middle slopes of Serra do Rio do Rastro, 21 km west of Lauro Müller, 700-1000 m, 3 Apr 1957, L.B. Smith et R.M. Klein 12343 (holotype: US [US00096115]!, isotypes: HBR [HBR0019549]!, K [K001206866]!, NY [NY00246259]!, R [R114719]!, UC [UC1079692]!).

Description: Subshrub to shrub; leaves lanceolate, base cuneate, pubescent, covered by malpighiaceous trichomes, stellate trichomes absent, margin serrate, 6-9 teeth per side; inflorescence with 1-3 basal pistillate flowers and 6-12 distal staminate flowers, floral nectaries glabrous on both staminate and pistillate flowers, staminate flower with 3-lobed petals, stamens 5; pistillate flowers without petals, styles glabrous, ovary and fruit covered by malpighiaceous trichomes.

Distribution and habitat: Chiropetalum phalacradenium is endemic to the states of Santa Catarina and Rio Grande do Sul, Brazil (Fig. 5 A ), and known from just a few records in three localities. It occurs in the Atlantic Forest province, on rocky outcrops and understory humid forest, at elevations of 800-1000 meters.

Flowering and fruiting: Flowers and fruits can be found from January to July.

Notes: Chiropetalum phalacradenium is a very restricted species and should be prioritized for conservation due to threats and low area of occupancy (12 km²) and extent of occurrence (310 km²) (Bachman et al. 2011Bachman S, Moat J, Hill AW, Torre J, Scott B. 2011. Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. ZooKeys 150: 117-126. doi: 10.3897/zookeys.150.2109
https://doi.org/10.3897/zookeys.150.2109... ). The species was collected by Smith and Klein, in 1957, and treated as C. gymnadenium by Smith & Downs (1959Smith LB, Downs RJ. 1959. Resumo preliminar das Euforbiaceas de Santa Catarina. Sellowia 11: 155-231.). In a review of the genus, Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) analyzed this collection (Smith et Klein 12343), and described it as a new species. In the protologue, the author cites the holotype and two isotypes, but now analyzing databases and reviewing herbaria collections, four other isotypes were found. Previously to this study, the occurrence of the species was cited for the states of Paraná, Santa Catarina and Rio Grande do Sul, but with the analysis of herbaria collections, field expeditions and recently collected specimens it is possible to confirm that the species is restricted to the states of Rio Grande do Sul (one collect) and Santa Catarina (eight collections to two localities). The records of C. phalacradenium from Paraná correspond to incorrect identification.

Selected specimens examined: BRAZIL. RIO GRANDE DO SUL: Morrinhos do Sul, 16 Dez 1995 (fl., fr.), J.A. Jarenkow et M. Sobral 2898 (PEL); SANTA CATARINA: Lauro Müller, Serra do Rio do Rastro, 21 km do centro de Lauro Müller, beira da estrada em frente ao monumento dos tropeiros, 28°23’57.48”S, 49°32’59”W, 19 Mar 2017 (fl. fr.), J. Külkamp 216 (ICN, RB); Beira da estrada ao lado da cachoeira, 28°23’55.32”S, 49°31’11”W, 19 Mar 2017 (fl, fr), J. Külkamp 217 (ICN); 28°23’57.12”S, 49°32’53.88”W, 21 May 2017 (fl, fr), J. Külkamp et al. 227 (ICN); Anitápolis, Trilha dos Índios, metade da trilha, 27°55’48.9”S, 49°18’14.2”W, 900 m, 26 Jul 2020, (fl.), J. Külkamp 1315 (FLOR, RB).

37. Chiropetalum puntaloberense Alonso Paz & Bassagoda, Comunicaciones Botanicas del Museo de Historia Natural de Montevideo 6(135): 1-2. 2009. Type: URUGUAY. ROCHA: Parque de Santa Teresa, Punta de los Loberos, Cerro Verde, 33^o56’42.8”S, 53^o30’22.9”W, 16 Oct 2003, E. Alonso-Paz et M.J. Bassagoda 3659 (holotype: MVM, isotypes: MVFQ, MVFA, MVJB).

Description: Subshrub to shrub; leaves ovate, elliptic to lanceolate, base acute to rounded, adaxial surface irregular, with simple, stellate and malpighiaceous trichomes, margin serrate, 13-29 teeth per side; 1-3 inflorescences per node, 1-4 basal pistillate flowers and 12-30 distal staminate flowers, floral nectaries glabrous in both staminate and pistillate flowers, staminate flowers with 5-7-lobed petals, stamens 5, pistillate flowers without petals, styles pubescent to the apex, ovary and fruit covered by simple, stellate and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum puntaloberense is endemic to Uruguay (Fig. 5 A ) and known from just a few records, all from one single location along the northern coast. It occurs in the Pampa province, at the edge of the sea with shrubby vegetation at low elevations, ca. 20 meters.

Flowering and fruiting: Flowers and fruits can be found from June to November.

Notes: Chiropetalum puntaloberense is a very restricted species and should be prioritized for conservation due to threats and low area of occupancy (2 km²) and extent of occurrence. This species has individuals which are highly branched at the base and have decumbent branches. It is similar to C. ramboi (Allem & Irgang) Radcl.-Sm. & Govaerts, which occurs in northeastern Rio Grande do Sul, Brazil. During the revision of Uruguayan herbaria, the type specimens were not found in the respective collections mentioned in the protologue, so we followed the information about the type contained in the protologue.

Selected specimens examined: URUGUAY. ROCHA: La Coronilla, Santa Teresa, punta de los loberos, 20 m, 28 Apr 2019, J. Külkamp et J. Iganci 801 (RB). Santa Teresa, Mar 1946, (fl. fr.), A. Lombarde 4685 (MVJB).

38. Chiropetalum quinquecuspidatum (A.Juss.) Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 92. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia quinquecuspidata (A.Juss.) Müll.Arg., Linnaea 34: 150. 1865. Croton quinquecuspidatum A.Juss., Euphorb. Tent. 110, 1824. Type: PERU. Dombey s.n. (lectotype [first-step] designated by Ingram 1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468b, [second-step] designated here: P [P00634976]!, isolectotypes: P [P00634977]!, P [P00634978]!, P [P00634979]!). Syntype remaining: Illustration in Euphorb. Tent. 110, pl. 8, fig. 26c. 1824.

= Chiropetalum peruvianum A.Juss, Annales des Sciences Naturelles 25: 22. 1832. [illegitimate superfluous name].

Description: Subshrub to shrub; leaves ovate, adaxial surface flat, base rounded, covered with simple, stellate and malpighiaceous trichomes, margin serrate, 9-22 teeth per side; 1 inflorescence per node, 1-4 basal pistillate flowers and 8-22 distal staminate flowers, floral nectaries glabrous on both staminate and pistillate flowers, petals of staminate flowers 5-7-lobed, stamens 5, petals acicular on pistillate flowers, glabrous styles, ovary and fruit covered by simple and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum quinquecuspidatum is endemic to Peru (Fig. 5 B ) and known by few records at elevations between 2300-2800 meters. It occurs in the Rondônia, Puna and Yungas provinces, on rocky slopes with sparse shrub vegetation.

Flowering and fruiting: Flowers and fruits can be found from September to April.

Notes: Jussieu (1824Jussieu AL. 1824. De Euphorbiacearum Generibus Medicisque earumdem viribus tentamen. Paris.) described Croton quinquecuspidatum citing Herb. Mus., referring to Herbarium P. He also provides an illustration of reproductive structures. However, the author does not indicate a type specimen. The only collection of Chiropetalum from Peru in P herbarium in 1824 is Dombey s.n.

Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) mentions that the holotype (Dombey s.n) is deposited in the herbarium P. However, there are four specimens of C. quinquecuspidatum collected by Dombey in the P herbarium. Thus, the author performs a lectotype first-step by not specifying a sample as type specimens. Apparently, Ingram (1980b) did not consider the illustration presented in the protologue to be original material. Here, we indicate Dombey s.n (P00634976) as the lectotype second-step of C. quinquecuspidatum according to art. 9.17. The four specimens of P have few differences, we chose P00634976 as the lectotype because it presents the collector’s original handwritten label, differentiating it from the other specimens. The illustration presented in the protologue by Jussieu (1824Jussieu AL. 1824. De Euphorbiacearum Generibus Medicisque earumdem viribus tentamen. Paris.) is treated as a remaining syntype. Chiropetalum peruvianum was combined from Croton quinquecuspidatus by Jussieu (1824), creating a superfluous name by not using the epithet quinquecuspidatus, which was available in Chiropetalum.

Selected specimens examined: PERU. BOLOGNESI: Ancash, Conay, 2700 m, 12 May 1950, (fl. fr.), R. Ferreyra 7349 (US). HUAROCHIRÍ: Lima, Matucana, 2400 m, 23 May 1940, (fl. fr.), E. Asplund 10986 (US). Sandia: Puno, 2300 m, 12 Nov 1987, L. Hoogte et C. Roersch 3534 (NY).

39. Chiropetalum ramboi (Allem & Irgang) Radcl.-Sm. & Govaerts, Kew Bull. 52: 478. 1997. Argythamnia ramboi Allem & Irgang, Rev. Bras. Biol. 36: 283. 1976. Type: BRAZIL. RIO GRANDE DO SUL. Torres do Sul: [Torres] at slopes at the hill, 15 Mar 1975, A. Allem et B. Irgang s.n. (holotype: ICN [ICN027340]!, isotypes: BH!, CEN!, DAV, U [U421115]!).

Description: Subshrub; leaves ovate, base rounded, covered with simple, stellate and malpighiaceous trichomes, margin crenate, 12-22 teeth per side; 1 inflorescence per node, 1-2 basal pistillate flowers, 2-8 distal staminate flowers, floral nectaries glabrous on both staminate and pistillate flowers, staminate flowers with 5-lobed petals, stamens 3-4, pistillate flowers with acicular petals, pubescent styles, ovary and fruit covered by simple, stellate and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum ramboi is endemic to the state of Rio Grande do Sul, in southern Brazil (Fig. 5 B ), and known from few records made at three locations on the coast, at elevations between 2-45 meters. It occurs in the Pampa province, in shrubby vegetation with sandy soil.

Flowering and fruiting: Flowers and fruits can be found around the year.

Notes: The specimen collected by B. Rambo in 1954 was identified as Argythamnia mollis Klotzsch ex Baill. by him, but upon studying the specimen, Allem & Irgang (1976Allem AC, Irgang BE. 1976. Two new species of Argythamnia (Euphorbiaceae) from Rio Grande do Sul, Brazil. Revista Brasileira de Biologia 36: 283-287.) realized that this corresponds to a new species, and then collected other specimens and described A. ramboi. Previous to the present study, the species was known only from collections made in the municipality of Torres, but recent field expeditions have identified new occurrences on Cidreira and Mostardas, also along the coast of the state of Rio Grande do Sul. In the protologue, the authors cite two isotypes for C. ramboi, in the BH and DAV herbaria, but these specimens were not found. Chiropetalum ramboi is an extremely threatened species due to urban expansion on the coast of the state of Rio Grande do Sul. In many locations, the vegetation has been suppressed for construction or by the large number of tourists trampling over native vegetation.

Selected specimens examined: BRAZIL. RIO GRANDE DO SUL: Cidreira, Fazenda Azaléia, 30°05’14.40”S, 50°13’53.5”W, 14 Aug 2017 (fl. fr.), R.M. Senna 1703 (HAS); Mostardas, Bacopari, Lagoa do Bacopari, 30°32’43.43”S, 50°25’45.8”W, 29 May 2017 (fl. fr.), J. Külkamp et al. 228 (ICN); Torres, Parque da Guarita, 29°21’11.20”S, 49°43’56.30”W, 13 Dec 2016 (fl. fr.), J. Külkamp 209 (ICN); Torre Sul, Parque da Guarita, 27 Jan 1953 (fl. fr.), D.B. Falkenberg 6051 (FLOR).

40. Chiropetalum ruizianum (Müll.Arg.) Pax & K.Hoffm., Pflanzenr. IV.147.vi (Heft 57), 94. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia ruiziana Müll.Arg. Linnaea 34: 151. 1865. Type: PERU. Prope Cheuchin, L.H. Ruiz et J.A.J. Pavon, s.n. (lectotype designated by Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468: G-DC [G005597]!, isolectotypes: HAL [HAL118975]!, MA [MA812824]!, MA [MA812825]!, MA [MA812826]!).

Description: Subshrub to shrub; leaves elliptic to ovate, base acute to rounded, with simple and malpighiaceous trichomes, stellate trichomes absent, margin serrate, 11-18 teeth per side; inflorescence with 1-3 basal pistillate flowers and 7-15 distal staminate flowers, floral nectaries pubescent in both staminate and pistillate flowers, staminate flowers with 5-lobed petals, stamens 5, pistillate flowers without petals, styles pubescent, ovary and fruit covered by simple and malpighiaceous trichomes.

Distribution and habitat: Chiropetalum ruizianum is endemic to central Peru (Fig. 5 A ) and known from a few records. It is distributed in the Yunga and Rondônia provinces, at elevations between 2700-3000 meters.

Flowering and fruiting: Flowers and fruits can be found from June to February.

Notes: Chiropetalum ruizianum is a poorly known species and similar to C. pavonianum. Further studies should be carried out to understand their morphological differences and phylogenetic relationships. Ingram (1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468b) designated the lectotype for C. ruizianum, and here we indicate three other specimens as isolectotypes deposited in the MA herbarium, where Ruiz and Pavón’s main collection is housed.

Selected specimens examined: PERU. DE LA MAR: Ayacucho, Entre Tambo e The Apurimac, 2700-2800 m, (fl.), Jun 1914, A. Weberbauer 5594 (US). CHAGLLA: 2800-2900 m, 1909-1914, A. Weberbauer 6696 (US).

41. Chiropetalum tricoccum (Vell.) Chodat & Hassl, Bull. Herb. Boissier. Ser 2. 5: 502. 1905Chodat RH, Hassler E. 1905. Chiropetalum. In: Durand E, Barratte G (eds.). Florae Lybicae Prodromus ou Catalogue Raisonne des Plantes de Tripolitaine. Bulletin de L’Herbier Boissier 2: 501-502.. Desfontaena tricocca Vell., Fl. Flum. p. 95. 1829 (1825). Type: BRAZIL. RIO DE JANEIRO: illustration in J.M.C. Vellozo, Flora Fluminensis, vol. 2, t. 146, 1831 [“1827”]! (lectotype designated here: original parchment illustration of Flora fluminensis t. 146 in the Manuscript Section, Biblioteca Nacional, Rio de Janeiro, indexed under digital object code mss1198651_149!).

= Chiropetalum gymnadenium Müll.Arg., Fl. bras. 11(2): 316. 1874. Type: BRAZIL. MINAS GERAIS: in umbrosis prope Villa do Presídio, L. Riedel 331 (holotype, G [G00434166]!), syn. nov.

Argythamnia lineata Baill., Adansonia 4: 288. 1864. Nomem nudum.

Chiropetalum lineatumKlotzsch, Archiv für Naturgeschichte 7: 199. 1841Klotzsch JF. 1841. Neue und weniger gekannte siidamerikanische Euphorbiaceen - Gattungen. Archiv für Naturgeschichte 7-1: 175-204.. Nomem nudum.

Description: Subshrub; leaves ovate to lanceolate, base rounded, covered by malpighiaceous trichomes, stellate trichomes absent, margin serrate, 13-28 teeth per side; inflorescence with 1-4 basal pistillate flowers and 12-26 distal staminate flowers, floral nectaries glabrous in both staminate and pistillate flowers, staminate flowers with 3-lobed petals, stamens 5, pistillate flowers without petals, styles glabrous, ovary and fruit covered by malpighiaceous and simple trichomes.

Distribution and habitat: Chiropetalum tricoccum is endemic to Brazil (Fig. 5 A ), occurring in Bahia, Minas Gerais, Rio de Janeiro, Rio Grande do Sul, and São Paulo. The species is distributed in the understory of open and riparian forest of the Atlantic, Parana Forest and Araucaria Forest provinces, between 200-720 meters above sea level.

Flowering and fruiting: Flowers and fruits can be found throughout the year.

Notes: Vellozo (1829Vellozo JMC. (1829) [1825]. Florae Fluminensis. Rio de Janeiro, Typographia Nationali.) described and illustrated Desfontaena tricocca based on a specimen observed by him in the “Alps Fluminensis”, Rio de Janeiro. The tome with the description was distributed in 1829 and the illustration only in 1831. In 1798, Vellozo’s original specimens were sent to the Royal Museum of Lisbon, where they were incorporated into the herbarium, possibly by Vellozo himself (Lima 1995Lima HC. 1995. Leguminosas da Florae Fluminensis - J.M. da C. Vellozo. Lista Atualizada das espécies Arbóreas. Acta Botanica Brasilica 9: 123-146.). Our recent research was unsuccessful in locating the original Vellozo’s collection, thus the lectotypification is necessary. As the illustration is the only original material of the species, we designate it as the lectotype of C. tricoccum, in accordance with the ICN.

Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) transferred Desfontaena Vell. to Argythamnia and mentioned the specimen Sellow s.n. (P), collected in Brasilia meridionalis (Rio Grande do Sul State). From this moment, taxonomists began to consider only this physical specimen and apparently no longer Vellozo’s illustration. However, this specimen corresponds to C. latifolium (see discussion in C. latifolium).

Chodat & Hassler (1905Chodat RH, Hassler E. 1905. Chiropetalum. In: Durand E, Barratte G (eds.). Florae Lybicae Prodromus ou Catalogue Raisonne des Plantes de Tripolitaine. Bulletin de L’Herbier Boissier 2: 501-502.) treats Desfontaena as a synonym of Chiropetalum, and describes C. tricoccum f. latifolia based on a specimen from Paraguay. Pax & Hoffmann (1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.), when analyzing the specimen (Sellow s.n.) of C. tricoccum cited by and the type specimens of C. tricoccum f. latifolia, concluded that they were the same biological entity, thus treating it as a synonym.

In all subsequent descriptions the morphological features used for recognition of C. tricoccum were the pubescent of floral nectaries and the 4-7-lobed petals, but in Vellozo’s illustration, the petals are 3-lobed, and nothing is mentioned about the nectary pilosity. Here we treat the specimen Sellow s.n. as C. latifolium. For the state of Rio de Janeiro, no other specimens of Chiropetalum were recorded, and the only known citation of the genus is the specimen on which Vellozo based the illustration.

Müller (1874Müller A. 1874. Euphorbiaceae. In: Martius CFP, Eichler AG. Flora Brasiliensis. 11, 2, 1-1752. ), when describing Argythamnia gymnadenia, uses the same morphological features presented by Vellozo in the illustration (3-lobed staminate petals). Analyzing the type and protologue, we conclude that C. gymnadenium is synonymy of C. tricoccum. According to Art. 9.1 note 1, we recognize Riedel 331 (G) as the holotype of C. gymnadenium because it is the only specimen found in the G herbarium collections, that is the main herbarium where the author worked (Stafleu & Cowan 1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.). Possibly, in LE there is a duplicate of Riedel 331, as it is the herbarium with the collector’s main collection. However, it was not possible to confirm this.

Chiropetalum lineatum was described as a new species for Brazil, but no description nor a type specimen were provided (Klotzsch 1841Klotzsch JF. 1841. Neue und weniger gekannte siidamerikanische Euphorbiaceen - Gattungen. Archiv für Naturgeschichte 7-1: 175-204.). Baillon (1864Baillon HE. 1864. D’Observations Botaniques. Adansonia 4: 1-289.) transferred C. lineatum to Argythamnia, establishing A. lineata and citing two specimens “(- Sellow, Brésil herb. Mus., ex herb, Berl. - A. S. H., cat. C1, n. 465)”. Later, Müller (1865Müller A. 1865. Euphorbiaceae, Argythamnia. Linnaea 34: 144-151.) treated correctly C. lineatum as nomem and synonym of A. tricocca.

Selected specimens examined: BRAZIL. BAHIA: Jussari, Serra do Teimoso, 04 Feb 1998 (fl. fr.), A.M. Amorim et al. 2593 (NY). MINAS GERAIS: Viçosa, Fazenda do deserto, 25 Sep 1930 (fl. fr.), Y. Mexía 5103 (NY, US). PARANÁ: Cerro Azul, Estrada de Turvo, Rio Ribeira, 22 Jan 1959 (fl. fr.), G. Hatschbach 5420 (MBM, US). RIO GRANDE DO SUL: Parobé, Santa Cristina do Pinhal, Oct 1987 (fl.), S. Diesel s.n. (PACA). SÃO PAULO: Botucatu, Usina Indiana, Aug 1972 (fl. fr.), Gottsberger et al. 925 (SP).

42. Chiropetalum tricuspidatum (Lam.) A.Juss., Annales des Sciences Naturelles (Paris) 25: 22. 1832. Chiropetalum tricuspidatum var. genuina (Müll.Arg.) Pax & K.Hoffm. Pflanzenr. IV.147.vi (Heft 57), 93. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia tricuspidata var. genuina Müll.Arg. Linnaea 34: 150. 1865. Odotalon tricuspidata (Lam.) Raf., Sylva Telluriana 33. 1838. Croton tricuspidatus Lam. Encyclopédie Méthodique, Botanique 2: 212. 1786. Type: CHILE. M. Dombey s.n. (lectotype [first-step] designated by Ingram 1980Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468b, [second-step] designated here: P [P00634982]!, isolectotypes: F [F971814F]!, P [P00634981]!, P [P00634983]!).

= Chiropetalum lanceolatum (Cav.) A.Juss., Annales des Sciences Naturelles (Paris) 25: 21. 1832. Chiropetalum tricuspidatum var. lanceolatum (Cav.) Pax & K.Hoffm. Pflanzenr. IV. 147. vi (Heft 57), 92. 1912Pax F, Hoffmann K. 1912. Euphorbiaceae - Acalypheae - Chrozophorinae. In: Engler A. (ed.) Das Pflanzenreich. Leipzig, Engelmann, IV.147 vi (Heft 57), 1-142.. Argythamnia tricuspidata var. lanceolata (Cav.) Müll.Arg. Linnaea 34: 150. 1865. Odotalon lanceolata (Cav.) Raf. Sylva Telluriana 67. 1838. Croton lanceolatus Cav. Icones et Descriptiones Plantarum 6: 38. 1800. Type: CHILE. BÍO-BÍO: Talcahuano, L. Neé s.n. (lectotype [first-step] designated by Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468, [second-step] designated here: MA [MA475593]!, isolectotypes: MA [MA475594]!).

= Chiropetalum ovatum Phil. Linnaea 29: 42. 1858. Type: CHILE. VALPARAÍSO: Prope Quillota, P. Germain s.n. (holotype: SGO [SGO051543]!, isotypes: BH, K).

Description: Subshrub; leaves linear to ovate, base acute to rounded, pubescent, covered by malpighiaceous trichomes, stellate trichomes absent, margin serrate, 3-8 teeth per side; inflorescence with 1-3 basal pistillate flowers and 5-30 distal staminate flowers, both pubescent, floral nectaries glabrous on both staminate and pistillate flowers, staminate flowers with petals 3-lobed, stamens 5, pistillate flowers with 5 petals, 3-lobed to entire, styles glabrous, ovary and fruit covered by malpighiaceous and simple trichomes.

Distribution and habitat: Chiropetalum tricuspidatum is endemic to Chile (Fig. 5 B ) and distributed in the forest understory in the Central Chilean and Valdivian provinces (Rivas-Martínez & Navarro 1994Rivas-Martínez S, Navarro G. 1994. Mapa biogeográfico de Suramérica. Madrid, Published by the authors.).

Flowering and fruiting: Flowers and fruits can be found from September to February.

Notes: Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) designated the lectotype for C. tricuspidatum, maybe the author considers the three exsiccatae of M. Dombey s.n. present in P as a lectotype. However, it was not specified. Here we consider as lectotype second-step of the name the specimen M. Dombey s.n. (P00634982) according to art. 9.17 of the ICN.

Ingram (1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468) also lectotypified C. lanceolatum Cav., but he did not specify the specimen chosen, since in the MA herbarium there are two specimens of L. Neé s.n. Thus following art. 9.17 of ICN, we designate here the lectotype second-step for C. lanceolatum, and consider L. Neé s.n. (MA475593) as lectotype. Some authors quote the collector Neeiten, when the correct name is Luis Neé. This confusion is caused because on the specimens it is written “Neé dedit,” indicating that the collection was carried out by him.

We agree with the synonymization of C. ovatum under C. tricuspidatum carried out by previous authors (Ingram 1980 b Ingram J. 1980b. A revision of Argythamnia subgenus Chiropetalum (Euphorbiaceae). Gentes Herbarum 11: 437-468). We consider the specimen P. Germain s.n. (SGO051543) as the holotype of C. ovatum, because the author of the name, Rudolf Amandus Philippi, worked for many years in the SGO collection, where most of the author’s type collections are deposited (Stafleu & Cowan 1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.). Ingram (1980b) mentioned the presence of isotypes in BH (fragment) and K, but we did not find these two samples. Chiropetalum tricuspidatum is used as a natural dye by some traditional communities in Chile. By infusing fresh or dried leaves in heated water, the color is blue and after a few hours it turns red (com. pers. of Marcela Ibañez Muñoz). This blue color after drying is observed in other species of Chiropetalum and Argythamnia, but it is not possible to extract the blue color using the same methods.

Selected specimens examined: CHILE. ACONCAGUA: Zapallar, 22 Feb 1947, (fl. fr.), O. Boelcke 4619 (BAA). CONCEPCION: Avenida Alemana, 15 Feb 1951, (fl.), E. Junge 2218 (US). Lanalhue, Jan 1929, (fl. fr.), J. Claude 5964 (US).

Philyra Klotzsch

PhilyraKlotzsch, Archiv für Naturgeschichte 7(1): 199. 1841Klotzsch JF. 1841. Neue und weniger gekannte siidamerikanische Euphorbiaceen - Gattungen. Archiv für Naturgeschichte 7-1: 175-204..

Type: Philyra brasiliensis Klotzsch.

Shrubs to treelets dioecious. Branches erect, with thorns, glabrous. Stipules developed, brown, persistent, paleaceous, lanceolate, trichomes simple, caducous. Leaves simple, alternate, petiolate, elliptic, base and apex acute, venation pinnate, margins entire, glabrous. Raceme axillary, flowers bracteolate, pedicelate; bracteole 1-4 per flower, paleaceous, lanceolate, pubescent, glabrescent or not. Staminate flowers 6-13 per inflorescence, pedicelate, dichlamydeous, actinomorphic; sepals 5, valvate, free, entire, lanceolate, simple trichomes; petals 5, valvate, free, entire, spatulate, glabrous; stamens 10-12; column with 2 whorls; staminodes 2, at the top of column; floral nectaries absent. Pistillate flowers 1-5 per inflorescence, pedicel long, articulated in half, dichlamydeous, actinomorphic; sepals 5, valvate, free, entire, acicular to lanceolate, trichomes simple; petals 5, larger than sepals, free, entire, spatulate to elliptic, glabrous; floral nectaries absent; ovary 3-locular, trichomes simple, caducous; styles 3, 1/2-proximal fused, 1/2-distal multifid. Capsule with 3 loci, 1-seeded, glabrous, columella persistent. Seeds spherical, surface smooth, gray to blackish.

Philyra is restricted to central and eastern South America (Fig. 6). The highest concentration of Philyra collections are from northeastern (Bahia state) and central-western (Mato Grosso do Sul state) Brazil and in the central region of Paraguay (Fig. 3 C ). All of these collection locations coincide with the distribution of Seasonally Dry Tropical forest, demonstrating the importance of this biome for the conservation of this lineage. In the phylogenetic reconstruction of Külkamp et al. (2023 a Külkamp J, Riina R, Ramírez-Amezcua YR et al. 2023a. Novelts in Acalyphoideae (Euphorbiaceae) systematics based on the molecular phylogeny of the subtribe Ditaxinae. Biology 12:173.), Philyra emerges as sister to other taxa of the tribe Adelieae, and thus was circumscribed in this tribe.

43. Philyra brasiliensis Klotzsch, Archiv für Naturgeschichte 7(1): 199. 1841Klotzsch JF. 1841. Neue und weniger gekannte siidamerikanische Euphorbiaceen - Gattungen. Archiv für Naturgeschichte 7-1: 175-204.. Argythamnia brasiliensis (Klotzsch) Müll.Arg., Linnaea 34: 144. 1865. Ditaxis brasiliensis (Klotzsch) Baill., Adansonia 4: 269. 1864. Type: BRAZIL. F. Sellow s.n. (lectotype designated here: P [P0063498]!, isolectotypes: BR [BR0000005102808]!, K [K0006002]!, TUB [TUB009146]!).

Description: Shrub to treelets dioecious; thorns on the branches; leaves elliptic, glabrous, venation pinnate, margin entire; inflorescences 5-14 mm long; bracts paleaceous, pubescent, glabrescent or not; 6-13 staminate flowers, with 10-12 stamens, glabrous, staminodes 2, pubescent, floral nectaries absent, 1-5 pistillate flowers, with pedicels larger than 12 mm long, styles multifid.

Distribution and habitat: Philyra brasiliensis is distributed in Argentina, Brazil, and Paraguay (Fig. 6). It occurs in the understory of seasonally dry tropical forest, at elevations ranging from sea level to 700 m, in the Atlantic, Cerrado, Chaco and Parana Forest provinces.

Flowering and fruiting: Flowers and fruits from July to April.

Notes: Philyra brasiliensis was described in detail by Klotzsch (1841Klotzsch JF. 1841. Neue und weniger gekannte siidamerikanische Euphorbiaceen - Gattungen. Archiv für Naturgeschichte 7-1: 175-204.). However, the author did not mention the type specimen in the protologue. When describing P. brasiliensis, Klotzsch worked as curator of the herbarium B (1833 to 1860); in this period, specimens of P. brasiliensis made by F. Sellow s.n. during his expedition to Brazil and Uruguay (1814 to 1831) were housed at B, as its main collections were sent to this herbarium and later duplicates were sent to others (Urban 1893Urban I. 1893. Biographische Skizzen. 1. Friedrich Sellow (1789-1831). Botanische Jahrbücher für Systematik. Pflanzengeschichte und Pflanzengeographie 17: 177-198.; Stafleu & Cowan 1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.). In the B, K, P, and TUB herbaria, there are duplicates of P. brasiliensis collected by Sellow s.n., all with original labels from Berolinense herbarium, indicating that they were received as a donation from B.

Baillon (1864Baillon HE. 1864. D’Observations Botaniques. Adansonia 4: 1-289.) transferred P. brasiliensis to Ditaxis (D. brasiliensis) and mentioned two specimens examined (F. Sellow s.n. [with the indication “Herb. Mus., ex her. Berl.”] and A. Saint-Hilaire 510). The collections made by Saint-Hilaire during the expedition to South America (1816 to 1822) were sent to the Paris Museum (Stafleu & Cowan 1976Stafleu FA, Cowan RS. 1976. 2nd edn. Taxonomic literature: A selective guide to botanical publications and collections with dates, commentaries and types. vol. 1. Utrecht, Bohn, Scheltema & Holkema. vol. 1.).

So, we have no evidence to affirm that Klotzsch used this collection of Saint-Hilaire in the original description of P. brasiliensis. Some specimens of P. brasiliensis collected by L. Riedel s.n. are indicated as types in different databases, but we also have no evidence that Klotzsch analyzed samples of this collection, as the collections from Riedel’s expedition were sent to St. Petersburg (LE) and later donated to other herbaria (Brummitt & Powell 1992Brummitt RK, Powell CE. 1992. Authors of Plant Names. Kew, Royal Botanic Gardens. ). Hence, and since the specimens at B herbarium were destroyed during World War II, here we consider the F. Sellow s.n as original material and chose the specimen P0063498 as lectotype of P. brasiliensis. We did not find any negative photos from B at the Field Museum of any specimen of Philyra, probably because the specimens were in the general collection and were not photographed.

Selected specimens examined: ARGENTINA. FORMOSA: San Cosme, Ruta 12, 23 km E de Corrientes, 10 Oct 1976 (fl.), A. Schinini et C.L. Cristobal 13656 (SI). Formosa, Aug 1919, (fr.), P. Jorgensen 3268 (SI). BRAZIL. MATO GROSSO DO SUL: Bonito, Parque Estadual da Serra da Bodoquena, Fazenda Boqueirão, 525 m, 18 Apr 2009, (fl. fr.), A. Pott et V.J. Pott 152929 (CGMS, RB). RIO DE JANEIRO: Italva, Quimbira, 300 m, 14 Dec 2019, (fr.), J. Külkamp et al. 1113 (HUEFS, MBM, RB, SP, US); Rio de Janeiro, 1822, (fr.) A.S. Hilaire 510 (P). No locality, no date, Riedel s.n. (GH00048511, K000600293, MO260337, S-R10601). PARAGUAY. CENTRAL: Ypacaray, Oct 1913, (fl.), E. Hassler 12323 (US - 2 sheets). Cordillera: Caacupe, Instituto Agricola Nacional, 80 m, 11 Sep 1981, (fl.), M. Vavrek et C. Cuevas 320 (US). PARAGUARI: Sapucai, Jul 1913, (fl. fr.), E. Hassler 11839 (US - 4 sheets).

Acknowledgments

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) Finance Code 001. We thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support to IC (process 309917/2015-8), JFAB (process nº 307068/2021-8), JK (process 141707/2020-8), JI (process nº 402157/2022-2), and Neotropical Grassland Conservancy for financial support to JI. We are thankful to all curators, researchers and technicians of the herbaria consulted. The authors also thank the Synthesys+ (Synthesis of Systematic resources-process ES-TAF-8188) for supporting the travel of JK to review the MA herbarium and the Smithsonian for a Cuatrecasas Award to JK that allowed the review of collections at the US and NY herbaria.

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