Reproductive biology of Stomatium bolusiae (Aizoaceae: Ruschioideae)

Flowers of Stomatium bolusiae are self-incompatible. The species exhibits crepuscular and nocturnal anthesis, exploiting two different pollination mechanisms. The structure of the hermaphroditic flower appears not to favour cross-pollination. The stigmata are never exposed to pollinating agents, which gain access to the floral rewards by forcing their way between the anthers. Clogging of the stigmatic surfaces by self-pollen is common. Nocturnal anthesis, concomitant with the nocturnal release of attractants and the offering of rewards, indicates that this species is primarily phalaenophilous and secondarily melittophilous, exhibiting a bimodal pollination system.