Variation in the Leaf Number of iArisaema iyoanum/isubsp. inakaianum/iand iA. ovale/ivar. iovale/i(Araceae)

摘要

Arisaema iyoanum Makino subsp. nakaianum (Ohba) H. Ohashi et J. Murata and A. ovale Nakai var. ovale are known to have one-leaved phenotype in both males and females;however, we discovered two-leaved individuals of these species. To elucidate the relationship between growth stage and leaf number of A. iyoanum subsp. nakaianum and A. ovale var. ovale, we conducted a morphological analysis of these plants. Our analysis suggested that the two-leaved individuals of A. iyoanum subsp. nakaianum and A. ovale var. ovale appeared only at the female phase. This suggested that one-leaved A. iyoanum subsp. nakaianum and A. ovale var. ovale individuals could not store the resources and hence changed to two-leaved individuals. This transformation could be explained by the fact that these species occur at high altitudes in mountain areas or regions covered in snow of the Japan Sea side, and their flowering time is also late compared with that in other sympatric Arisaema species.