Flowering and mating system in hybridizing Carpobrotus (Aizoaceae) in coastal California

Patterns of flowering and pollination visit of Carpobrotus spp. were examined to determine the hybridization potential between the introduced succulent perennial Carpobrotus edulis and its native congener, Carpobrotus chilensis, in coastal California. Both species flower from March to July and both are visited by the same Thysanoptera and Coleoptera taxa. Flowers from hybrid-appearing individuals were intermediate in corolla diameter. Emasculation and bagging experiments suggest that C. edulis and hybrid morphotypes have facultative agamospermia, whereas C. chilensis has facultative self-fertilization. Emasculated C. chilensis did not set seeds. Pesticide application and flower bagging suggest that 80% of seed set in self-pollinated C. chilensis flowers is mediated by thrips. Our results suggest that there is high potential for natural hybridization in Carpobrotus species in California and that Carpobrotus populations can persist without cross-pollination.