Floral biology of the introduced species, Hedychium coronarium Koen., naturalized in Brazil, was investigated in the period between November 2003 and July 2004. The species occurs in swamps in large areas of the country, and also along roadsides in the municipality of Teresópolis, Rio de Janeiro. The flowers of H. coronarium are white, zygomorphic, hermaphroditic and nectariferous. They have nocturnal anthesis and emit a strong odor spreading long distances. The staminodes are a “unit of attraction” for floral visitors. The androecium is composed of a sole fertile stamen with pollen grains in “pollenkitts”. The stigma is green, wet, concave and surrounded by uniform hairs. The species is selfincompatible, presenting low rates of natural fruit set. The flowers of H. coronarium are important nectar and pollen sources for the insects that visit them. Flowering follows an annual pattern, shows asynchrony in the population level and lasts from January until April. Fruiting occurs from March until May.