A New Species and Nomenclatural Changes in Neotropical Platymiscium (Leguminosae: Papilionoideae: Dalbergieae)

Abstract

Summary. One new species, Platymiscium jejunum from Mexico, is described, nine new infraspecific combinations are proposed; and new synonyms are added to P floribundum var. floribundum, P floribundum var. latifolium, and R pinnatum subsp. pinnatum var. pinnatum. The Neotropical genus Platymiscium comprises 18 species (28 taxa) of trees (Klitgaard, in prep.). Four species are morphologically variable and geographically widespread, and 14 species are more restricted, some being very narrow endemics. The genus is uniquely defined within the Leguminosae by the following combination of features: (a) opposite leaves, (b) interpetiolar stipules, (c) yellow papilionoid flowers borne in axillary racemes, and (d) one-seeded samaroid fruits. Platymiscium species occur from about 30'N in Mexico, throughout much of Central and South America to 20'S in eastern Brazil. Species have successfully colonised dry (nine species) as well as humid (nine species) habitats. The systematic study (Klitgaard 1995 unpubl. PhD thesis), from which the present paper is extracted, and a future monograph of the genus (Klitgaard, in prep.) are based on the study of more than 1100 herbarium collections from the following herbaria: AAU, B, BAF, BH, BHCB, BHMH, BM, C, CEPEC, CVRD, EAC, F, FHO, G, GH, HBG, HRB, HUEFS, IAN, IBGE, INPA, IPA, K, L, LD, NY, M, MAD, MBM, MEXU, MG, MO, OXF, P, QAME, QCA, QCNE, R, RB, RC, S, SI, SP, SPF, U, UB, UC, UEC, UPS, US. All the material cited has been seen by the author, unless otherwise indicated.