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.