The gynocecia of Australian restionaceae: Morphology, anatomy and systematic implications

Abstract

Gynoecial structure has been much emphasised in the supraspecific classification of the Restionaceae. Recent work on the culm anatomy, palynology and chemistry has indicated extensive parallelism in their evolution. Detailed anatomical investigations presented here show that the apparently similar gynoecia of some African and Australian Restionaceae are indeed the result of convergence. Reduction in some of the Australian genera can be shown to be the result of convergence, but the range of reduction routes is smaller than in the African Restionaceae. Several phylogenetically interesting features of the female flowers are documented. The perianth may consist of six undifferentiated, more or less membranous tepals, or they may be cartilaginous, with the outer lateral tepals conduplicate. In the latter case there is frequently a reduction to four tepals, paralleled by reduction in the gynoecium. The gynoecial information by itself is not adequate to formulate a phylogenetic hypothesis for the Australian Restionaceae, but should provide valuable information for such a project.