The Enantiostyly and the Pollination Biology of Monochoria korsakowii (Pontederiaceae)

Abstract

The flower morphology and pollination biology of Monochoria korsakowii were studied in natural and transplanted populations. The plant has somatic enantiostyly, i.e., each plant bears two morphs of flowers, left- and right-handed flowers, witla the style deflection to the left and right, respectively. The enantiostyly is accompanied by a stamen dimorphism : each flower has five small and one large stamens, the large anther and the stigma are symmetrical with respect to the median plane of the flower. The major pollinators observed were Apis cerana japonica, Xylocopa circumvolans and Bombus spp. The large anther of a flower morph touches the same position of bee's abdomen as the style of the other morph, thereby apparently facilitating intermorph pollination. However, since the enantiostyly is somatic, this seems to lead to cross-pollination only when flowers of only one morph, by chance, are open on an individual. The flower was found to be self-compatible and capable of setting seed even in the absence of pollinators. It was the small stamen that contributed the autogamy.