Pollinators of Oxypetalum (Asclepiadaceae) in southeastern Brazil.

Floral visitors of seven species of Oxypetalum were registered in Viçosa, State of Minas Gerais. O. appendiculatum, O. banksii subsp, banksii, O. alpinumn var. alpinum and O. pachyglossum are pollinated by wasps, being Polybia ignobilis (Vespidae) a pollinator of these four species. It seems that P ignobilis promotes interspecific pollinations mainly between O. alpinum var. alpinum and O. pachyglossum, two species with very similar floral morphology. O. jacobinae, O. mexiae and O. subriparium are pollinated by bees. Wasps and bees carry one, two, three or several pollinaria in the mouthparts. O. mexiae, an endemic species in Viçosa, seems to present reproductive limitations, since its flowers are seldom visited.