Psychotria L. (Rubiaceae) is the genus with the most heterostylous species in the angiosperms. The objective of this study is to describe floral biology, phenology, reproductive system, and pollinators of Psychotria poeppigiana Müll. Arg. The terminal inflorescences are capitate with red bracts and yellow flowers, and presented two different morphs: pin and thrum, characterized by hermaphroditic flowers with different lengths of styles and opposed position of the anthers (reciprocal herkogamy). Dimorphism was also observed in the size of anthers, pollen grains and stigmatic surfaces. Controlled pollination revealed self-incompatibility and intramorph-incompatibility at the level of stigma and style. Wasps, butterflies and hummingbirds visited the flowers, especially in early morning. According to the frequency of visits and an efficient transport of pollen between floral morphs, the hummingbird Thalurania furcata was the main pollinator. Little nectar (max. 8µl) was produced during the opening of the flowers (5:00-7:00h). Because of vegetative reproduction the species forms clumps.
Psychotria; distyly; self-incompatible; pollination; gallery forest
