Cuphea melvilla Lindlay (Lythraceae): uma espécie do Cerrado polinizada por beija-flores

cuphea melvilla is a peculiar species of a mostly melittophilous genus. various aspects of the floral and reproductive biology of two groups of individuals, which occur on the edge of gallery forests on the panga stream (in uberlandia, southeastern brazil), were studied. observations were carried out during the flowering season of 1999. cuphea melvilla is a shrub with floral features adapted to hummingbird pollination. it has a long flowering period, from january to july, but flowers the most during the rainy season. the flower tube of this species is of hypanthial origin, has a spur at the base, and accumulates nectar, which is produced by a nectary at the base of the ovary. the flowers were protandrous but different floral phases were present from the top to the bottom of the simple racemes. the species appears to be self-compatible but non-apomictic and needs active pollination to form fruits. pheathornis pretrei, amazilia fimbriata, thalurania furcata, eupetomena macroura and chlorostilbon lucidus (female) were the hummingbird species observed visiting and pollinating the c. melvilla flowers. amazilia fimbriata and c. lucidus showed occasional territorial behaviour in relation to the c. melvilla populations, whereas p. pretrei seemed to be trapliner. thalurania furcata and e. macroura visited the studied populations sporadically. amazilia fimbriata, c. lucidus and p. pretrei were considered the main pollinators for the studied populations due to their frequency. the flower features of cuphea melvilla that are related to hummingbird pollination appear to be derived within the genus, and bird pollination, within different sections of the genus, indicate a convergent adaptation.