Pollen Presenter and Pollen Morphology of Banksia L.f. (Proteaceae)

Abstract

The morphology of the pollen presenter and pollen was studied in 79 taxa of Banksia using scanning electron microscopy. There were three major types of pollen presenter. Elongated and cylindrical structures were characteristic of the series Banksia, Crocinae, Tetragonae, Coccineae and some species of the Cyrtostylis and Abietinae. Short and cylindrical pollen presenters were found in the series Salicinae, Quercinae, Prostratae and some species of the Cyrtostylis. Short and ovoid pollen presenters were found in the series Grandes and Dryandroideae, and in the species B. brownii and B. ericifolia of the Spicigerae and B. pulchella of the Abietinae. The pollen-receptive stigma cells of all taxa were enclosed within a groove, which in the majority of species was obliquely terminal and longitudinal. Subterminal grooves, all of which were longitudinal, except that of B. speciosa which was located laterally, were observed in a few species. Pollen of all taxa had two germination pores, at opposite ends of a cylindrical, ovoid or crescent-shaped grain. There was a higher level of between species and between group consistency in pollen grain than in pollen presenter structure. The results have implications for both the interspecific fertility relationships and taxonomy of the genus.