The aspects of floral biology and reproductive system of Gliricidia sepium were studied from March to October of 1999, from 5:30am to 5:00pm, in an introduced population at Embrapa Semi-Árido, Petrolina, in the State of Pernambuco, Brazil. Fifteen plants were marked and observed every two weeks for the study of phenology. For the study of floral biology and morphology, flowers and inflorescences were marked and observed until fruit set. The visitors of flowers were observed during all time of the experiment, when frequency, time and duration of their visits were registered. G. sepium has a cornucopia pattern of flowering and the peak of this phenophase occurs in August. The flowers are grouped in axilar racemes, with centripetal development, and the anthesis occurs at 5 to 45 flowers/day. The flowers have the typical organization of papilionaceae, corolla of magenta color and the central region of flag of cream color, which functions as nectar guide. The anthesis is diurnal, occurring at around 6:00am, and the lifetime of flowers is around 10 hours. Apidae and Anthophoridae bees and Hesperiidae moths are the most frequent visitors. Xylocopa griscesens, X. frontalis and Eulaema nigrita were considered the main pollinators of this species. G. sepium is a species which produces fruits only after cross-pollination (51.6%).
pollination; reproductive system; Gliricidia sepium; floration; frutification
