The reproductive ecology of piassava palm (Attalea funifera Mart.) was investigated for 19 months in the Atlantic forests of eastern Brazil. Its breeding biology is characterized by the production of functionally female, male and bisexual inflorescences. Staminate sterility is positively correlated with number of pistillate flowers. Staminate and pistillate flowers are receptive at anthesis. Bagging tests for apomixis were negative. Although geitonogamy can occasionally occur, outcrossing predominates. Pollen is relatively dry, but wind pollination is not a significant factor in cross pollination. Although inflorescences are visited by large numbers of insects, pollination is effected mainly by small sap beetles (Mystrops sp.) and weevils (Phyllotrox tatianae), which feed and breed in fertile staminate flowers. Pistillate flowers, which offer no reward to pollinators, appear to attract insect visitors by olfactory and visual imitation of staminate flowers, that is, via Bakerian mimicry. Flower production, fruit maturation, leaf production and leaf abscission occur continuously throughout the year. Flowering exhibits a distinct peak during the warmest months (Dec–Apr). Given its ubiquity throughout the region, A. funifera may well serve as a flowering and fruiting keystone species.