| Abstract: | Dioecy in the Solanaceae is rare, occurring in < 1 percent of the species worldwide and known in only two species from South America. We report the occurrence of cryptic dioecy in the Neotropical genus Deprea. Studying herbarium material of the Venezuelan endemic D. paneroi revealed morphological distinctions that tentatively served to divide collections into male and female morphs. This discovery prompted investigation of population structure, crossing studies, and morphometric analyses of 95 individuals from the largest known wild population and a small sample of greenhouse‐grown plants. About 60 percent of the population was reproductive, and of these, nearly equal numbers exhibited female or male characteristics. Plants that bore fruit and small sterile anthers were characterized as female; those that lacked fruit but produced pollen in large anthers were characterized as male. The morphology, receptivity, and developmental phenology of pistils were identical in both forms. Crossing studies revealed significant enlargement of the ovaries in open‐pollinated female flowers and female X male hand‐pollinations. The ovaries in open‐pollinated male flowers and male X male hand‐pollinations never enlarged. These results suggest that the only legitimate combination is female X male. Dioecy in the family and possible mechanisms for the evolution and maintenance of dioecy in D. paneroi are discussed. |
