Natural Hybrid Populations between Chasmogamous and Cleistogamous Species, Ainsliaea faurieana and A. apiculata (Asteraceae; Mutisiae): Morphology, Cytology, Reproductive Mode and Allozyme Variation

Abstract Ainsliaea apiculata is a cleistogamous perennial. This species occasionally hybridizes with A. faurieana on Yakushima Island, Japan and the hybrids are fertile. A cytological study of these hybrids revealed no irregularity in their male meiosis and the occurrence of genetic segregation through successful reproduction. Allozyme variation provided evidence for segregation through selfing in the hybrids. Observation on pollen grain number showed that these hybrids have cleistogamous flowers in various frequencies. Cleistogamy is dominantly inherited in the hybrids and selfing by cleistogamous flowers is considered to contribute to the formation of hybrid populations.