Pollination of Nematanthus brasiliensis - An Epiphytic Gesneriaceae Endemic to the Southeastern Atlantic Forests of Brazil

摘要

The floral biology and visitors of Nematanthus brasiliensis were studied in a submontane rainforest in Mangaratiba, Rio de Janeiro, Brazil. This species presents a flowering peak between October and February. Its flowers usually last eight days and show marked protandry. The floral features of N. brasiliensis suggest an ornithophilous pollination syndrome: tubular shape, pendent position, brightly colored, absence of perceptible odors. Nectar volume (21.3 mul) and sugar concentration (31.8%) are alsoindicative of bird pollination. Field observations have verified this hypothesis : the flowers of N. brasiliensis are visited by two hummingbird species, Ramphodon naevius and Phaetornis ruber. Our data show that P. naevius is the main pollinator of N.brasiliensis and that it promotes cross-pollination. In addition, configuration of the reproductive structure in N. brasiliensis may avoid inter-specific pollen competition in style.