A REVISION OF HELIETTA AND BALFOURODENDRON (RUTACEAE-PTELEINAE)

A taxonomic revision of two of the four genera in the rutaceous subtri be Pteleinae is presented. Helietta and Balfourodendron are neotropica l taxa that share trifoliolate leaves, terminal thyrses, small isostem onous flowers, syncarpous 4-5-carpellate ovaries, winged fruits, and s eeds with endosperm. They differ mainly in that Balfourodendron has le af domatia and a samara with broad verticillate wings, while Helietta lacks domatia and has a fruit that separates into free samaroid merica rps, each with a dorsal wing. Two species are recognized in Balfourode ndron, B, riedelianum and B, molle, the latter being a new combination . Helietta comprises 8 species, including a new combination, H. glazio vii. Keys to the species, descriptions, synonyms, illustrations, and c omments on the geographic distribution and ecology of each taxon are p resented.