XVI International Botanical Congess

Androdioecy is a rare mating system comprised of male-flowered plants and hermaphroditic-flowered plants in the same population. Most species that have been described as morphologically androdioecious have been found to be functionally dioecious when experimentally studied. Populations of white mangrove (Laguncularia racemosa L.: Combretaceae) appear to be morphologically and functionally androdioecious in Miami, FL and on San Salvador Island, Bahamas. One San Salvadoran population lacks male plants and appears to be functionally hermaphroditic. Results of experimental pollinations performed in Miami and on San Salvador are described. Hypotheses and further tests to understand this mating system and the factors responsible for the maintenance or loss of males are discussed.