XVI International Botanical Congess

Lophate pollen grains, characterised by patterns of prominent ridges, occur in members of tribes Arctoteae, Barnadesieae, Lactuceae and Vernonieae of the Asteraceae. The functional morphology of these distinctive pollen grains has been discussed by several authors since the pioneering studies of Wodehouse (1935). Lophate pollen morphology has been variously interpreted as an adaptation for pollination, increased mechanical strength and/or harmomegathy (the process of accommodating volume changes resulting from different states of pollen hydration). Phylogenetic studies suggest that lophate pollen has arisen independently in the four tribes and, for the Lactuceae at least, more than once within the tribe. The purpose of this paper is to reconsider the function of lophate pollen in the light of phylogenetic evidence.