Heliconia bihai is a highly polymorphic species. Populations of the species are distributed throughout the Lesser Antilles and northern South America; the most obvious sign of polymorphism is manifested through differences in bract color. This variation has been attributed to pollinator‐mediated selection, but other processes are also plausible. To test the potential contribution of drift in the evolution of phenotypic variation in this system, we examined the distribution of morphological and genetic variation within and between populations of H. bihai in the Caribbean islands of St. Vincent and St. Lucia. Morphological characterization was limited to flower and inflorescence characteristics, including bract color. AFLPs were used to investigate levels of genetic diversity within and between populations. Genetic similarity among individuals was equivalent to that expected for conspecific individuals. Levels of AFLP and population subdivision were high and were comparable to those of outcrossing species i...