Abstract
The new genus Alatococcus (Sapindaceae) is described from Espirito Santo, Brazil. Alatococcus seems to be closely related to Scyphonychium of northeastern Brazil, as they both share similar vegetative morphology, flowers with zygomorphic calyx, fruits with indehiscent mericarps, and isopolar, tricolporate pollen grains. They however differ by the shape of the nectary disc, petal appendages, mericarps, and pollen shape and ornamentation. The new species Alatococcus siqueirae is described and illustrated.