New Natural Hybrid of Arisaema (Araceae), Distributed around Mt. Yatsuzura, in Shikoku, western Japan

Abstract

Morphologically intermediate plants between Arisaema tosaense and A. undulatifolium subsp. uwajimense were recently found in Ehime and Kochi prefectures, Shikoku, Japan. The putative hybrids have the reproductive characteristics of A. tosaense, but purplish-dark brown, short pseudostems similar to A. undulatifolium subsp. uwajimense. Molecular analysis of nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region using PCR-RFLP indicates that these putative hybrids have a combined pattern of the two putative parental species. The chloroplast DNA (cpDNA) trnL intron sequences of all the putative hybrids and A. tosaense were identical. The results suggest that the plants are hybrids between A. tosaense and A. undulatifolium subsp. uwajimense and were formed by gene exchange via pollen grains transferred from A. undulatifolium subsp. uwajimense to A, tosaense.