XVI International Botanical Congess

We present data on flower morphology, pollination and breeding system of Abutilon rufinerve in the Atlantic rainforest of SE Brazil. Abutilon is a self-incompatible treelet that is visited and pollinated by one species of bat and four hummingbirds. Abutilon exhibits interplant variation in floral color and size, and flower features intermediate between bat and hummingbird pollination syndromes. Although hummingbirds are the most frequent visitors to flowers (66% of visits), exclusion tests resulted in similar fruit-sets for nocturnal and diurnal pollinators. Bats, however, are more effective pollinators, accounting for ca. 70% of the seed-set in 1997 and 1998. Despite the fact that Abutilon employs a variety of pollinating agents, the lack of temporal variation in pollinator effectiveness might lead to specialization in this system.