A synopsis of Oxypetalum (Apocynaceae) in Bolivia, with the description of one new species and a key to species in Bolivia.

We present a synopsis of Oxypetalum (Asclepiadoideae, Apocynaceae) in Bolivia. In addition, one new species, Oxypetalum urceolatum, is described, illustrated, and compared to its putative closest relatives. Oxypetalum urceolatum forms a complex with O. erianthum, O. brachystemma, O. dactylostelma, O. dombeyanum, O. molle, O. pearsonii, and O. fuscum. Morphologically, O. urceolatum appears most closely related to O. dactylostelma, from which it differs in having a conical, rather than expanded, style-head appendage and a glabrous, not pilose, throat to the corolla. In addition to this new species, we present a key to species of Oxypetalum in Bolivia.