Allozyme analysis of the hybrid origin of Arisaema ehimense (Araceae)

Allozyme diversity was examined in the Japanese jack-in-the pulpit species, Arisaema serratum and A. tosaense, and their putative hybrid species, A. ehimense (all diploid). Arisaeme ehimense contains mostly alleles found in one or both of the putative parent species but few unique alleles, partially supporting the hypothesis that A. ehimense is of hybrid origin from the two species, although the possibility that A. ehimense arose via divergent speciation cannot be excluded. Because only limited information was gained from the survey of allozyme variation, additional taxon-specific markers from A. serratum and A. tosaense are required to test rigorously the hybrid origin of A. ehimense. A phenogram based on allele frequencies suggested that introgression occurs between A. serratum and A. tosaense where these species are sympatric.