Floral heteromorphism in Dais cotinifolia L. (Thymelaeaceae) : a possible case of heterostyly

Floral heteromorphism is reported in Dais cotinifolia L. (Thymelaeaceae) and is associated with an unusual array of ancillary features. The apetalous flowers have three different style morphologies. The upper whorl of stamens in the mid style morph are mid-length, instead of having a whorl of long stamens, as in other tristylous species. There are differences in the morphology of the stigmatic papillae and pollen sculpturing among the three style morphs, however, there is no difference in pollen size. The perianth in the mid style morph is significantly shorter than the perianth in the short and long style morphs. This unusual array of features in what appears to be a tristylous species suggest that floral heteromorphism may be more variable than previously thought. It is also apparent that a more complete survey of tropical Thymelaeaceae (and tropical angiosperms in general) for floral heteromorphism is needed.