New or critical Euphorbiaceae from the Americas

Abstract

This paper consists of the descriptions of various new species and varieties, a new genus Moacroton from Cuba, and critical notes and records, reductions, and transfers. Unless otherwise stated, the types of the forms herein described are preserved in the herbarium of the Arnold Arboretum.Phyllanthus Linnaeus Phyllanthus vichadensis sp. nov.Fruticulus caules strictos plures erectos e rhizomate perenni edens, ramis glaberrimis exalatis subexalatisve. Foliis ellipticis carnosulis enerviis 5-7 mm. longis, 2 mm. latis, utrinque aequo iure acuminatis petiolulo ca. 1 mm. longo, stipulis subsetaceis integris ca. 2 mm. longis. Floribus secus apicem ramulorum dispositis, £ ad 3 capitulatim aggregatis subsessilibus, 9 longius pedicellatis saepissime singulis. Perianthio S ca. 2 mm. longo 2.5 mm. lato 5-lobo, antheris 3 in columna ca. 1.5 mm. alta coalitis longitudinaliter dehiscentibus, columna basi incrassata revera haud glandulosa. Perianthio 9 magnitudine fere 6 5-lobo, lobis costatis rotundato-ellipticis, disco nullo subnullove, ovario globuloso depresso ca. 1 mm. in anthesi magno, stylis 3 ca. 1 mm. longis e basi liberis subliberisve apice bilobato partitis, pedicello sub fructu nonnihil apice incrassato ad 4 mm. longo.Colombia: Comisaria El Vichada: About 70 km. southeast of Orocue, Haught 2779. This new species is described as an inconspicuous perennial of the open llanos. Its habit is reminiscent of P. diffusus Kl., an annual weed with which it was originally confused in the herbarium. Fragments of Lepricur 319 and Schomburgk 529 in our herbarium show that it definitely differs from P. hyssopijolioides H. B. K. (well represented by Williams 15945a; Venezuela, Amazonas, Puerto Ayacucho) and P. guianensis Kl. in foliage as well as in floral characters. It may be remarked that the habit and gross morphology of the latter is reminiscent of the species in the vicinity of P. caroliniensis Walt.Frutex lignosus innovationibus pallide ochraceis velutino-hispidis dcmiiin glabratis. Foliis pro more ovatis, interdum lanceolatis vel oblongo-ovatis. 5-8 cm. longis, 2-5 cm. latis, olivaceo-brunneis vel brunneis, submembranaceis, subtus laxius stellato-pubescentibus subgriseis, supra pilis subsimplicibus more proprio adpressis setoso-pubescentibus, apice breviter acuminatis, basi rotundatis vel leviter cuneatis, margine subintegris ciliatis, nervis adscendentibus ca. 7-9-jugis, primo jugo ramoso, glandulis stipulisque

Phylogenetic reconstruction prompts taxonomic changes in <I>Sauropus</I>, <I>Synostemon</I> and <I>Breynia</I> (<I>Phyllanthaceae</I> tribe <I>Phyllantheae</I>)

“…The close relationship between Breynia and Sauropus was noted by several authors (Croizat 1940, Airy Shaw 1980a, b, 1981a, but they never united the genera. The last complete revision of Breynia was made by Müller Argoviensis (1863,1866), and the last revision of Sauropus dates back to Pax & Hoffmann (1922).…”

New Euphorbiaceae from Mexico

“…In her thorough treatment of the genus Croton in the state of Guerrero, Mex ico, Martinez (1995) treats this new variety as C. ramillatus var. insignilobis (Croizat 1945). Although I have examined only a limited amount of material, most of which is the same as that available to Croizat, I have doubts as to the validity of var.…”

Revisión taxonómica de Argythamnia subgénero Ditaxis (Euphorbiaceae) en México

“…Sin embargo, aún después del trabajo de Pax y Hoffmann, el estatus taxonómico de Ditaxis siguió inconsistente; por ejemplo, Johnston (1924) reconoció al género Ditaxis cuando describió D. brandegeei var. intonsa, mientras Croizat (1945) hizo el cambio de esta especie a Argythamnia considerando a Ditaxis como subgénero.…”

“…Por ejemplo, entre los taxónomos que lo han reconocido a nivel de género destacan: Zuccarini (1832), Heller (1898Heller ( , 1912, Rose y Standley (1912), Pax y Hoffmann (1912, 1914, 1931, Johnston (1923), Eastwood (1929), Punt (1962), Webster (1994), Steinmann y Felger (1995, 1997, Radcliffe-Smith y Govaerts (1997), Govaerts et al (2000), Martínez et al (2002), Steinmann (2002) y Kiesling (2003). Al igual que Chiropetalum, Ditaxis ha sido incluido como una sección de Argythamnia por Müller (1865Müller ( , 1866 y Bentham (1880) y como subgénero del mismo por Croizat (1945), Ingram (1953Ingram ( , 1956Ingram ( , 1957Ingram ( , 1964Ingram ( , 1967Ingram ( , 1980a, Johnston y Warnock (1962) y McVaugh (1995. Además se ha reconocido simplemente dentro de Argythamnia (sin distinción de categoría infragenérica) por Gray (1870), Millspaugh (1889Millspaugh ( , 1896, Greenman (1898Greenman ( , 1905, Rose (1895), Brandegee (1906Brandegee ( , 1908 y Jepson (1936).…”