Systematic studies of Aristolochia sensu lato

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Morphological and molecular phylogenetic examinations were made to establish a phylogenetic systematics of the genus Aristolochia sensu lato, including Pararistolochia. Herbarium specimens were examined in representative herbaria in Japan and also in Kew and Edinburgh Botanic Gardens. Living specimens, accumulated and maintained in the Botanical Gardens, University of Tokyo and in Setsunan University were used for chromosome observation and molecular phylogenetic analysis. Chromosome numbers were newly determined for 25 species, which suggests that 2n = 32 is specific to subgen. Siphisia. As 2n = 16 was found in some species placed in the basal clade, 2n = 32 is considered to be tetraploid based on x = 8. Subgen. Aristolochia consists of two subgroups with 2n =12 and 14, respectively. The nucreotide sequences of the matK gene on the chloroplast DNA were analyzed with an autosequencer afrter amplified with PCR. A phylogenetic tree for 57 species of the genus was constracted on the bases of the sequence data of the matK gene. The configulation of the tree was in accordance with current system of Aristolochia by Gonzalez (1999). Pararistolochia appeared to be a sister group of subgen. Aristolochia. To analyze specific diversity of A. kaempferi complex in Japan and Taiwan, haplotype and phylogenetic analysis usisng matK gene sequence were also made on various samples of the complex. Haplotypes were recognized to be differentiated regionally and A. kaempferi, distributed widely in central and western Japan, were found not to be monophyletic.