XVI International Botanical Congess

Secamonoideae are the missing link between Periplocoideae and Asclepiadoideae, the two main subfamilies of Ascle- piadaceae. We studied the pollination of two Secamone species : S. geayi and S. buxifolia, counting the number of pollinaria inserted and removed per flower. In S. geayi, 3 flower stages were examined Ð young (white), mature (pale yellow) and faded (dark yellow), in S. buxifolia where no color change occurs, only faded flowers were sampled. Pollinaria morphology is different between the two species. S. geayi has pollinia grouped by four, whereas pollinia of S. buxifolia are free from each other. In S. geayi insertion or removal occur in 50% of flowers whereas in S. buxifolia there is only 23.6 % of the flowers with insertions. These differences might due to the different color of flowers or to pollinaria morphology but this needs to be studied further.