Self-incompatibility in the Commelinaceae

This paper reports on a survey of self-incompatibility in 110species of 22 genera in the family Commelinaceae. Genera fromboth tribes, Tradescantieae and Commelineae are included. Fifty-fivespecies were found to be self-incompatible, 50 species self-compatible,and five species comprised individuals which were self-incompatibleand individuals which were self-compatible. This variabilityand its possible evolutionary significance are discussed. Self-incompatible species had actinomorphic flowers and themajority of these were in the Tradescantieae. Species with zygomorphicflowers which were more commonly found in the Commelineae wereself-compatible. The ubiquitous presence of binucleate pollengrains supports previous data that self-incompatibility is ofthe gametophytic type. The site of pollen tube arrest, however,was on the stigma at or near the base of the stigma papillacells. There were two exceptions to this viz. an unnamed Dichorisandraspecies and Siderasis fuscata where pollen tube arrest was stylar. The significance of these data to taxonomy also receives comment. Commelinaceae, incompatibility, self-compatibility