XVI International Botanical Congess

The subg. Rhizirideum of the genus Allium L. (Liliaceae) is characterized by possessing rhizomes. Other morphological characters however, are few and quite variable. Sequence data were obtained to elucidate the phylogenetic relationships among sections within this subgenus. Sequences of ITS were determined for 16 taxa of subg. Rhizirideum and representatives of other subgenera as outgroup. Phylogenetic analyses of ITS sequences by neighbor-joining analysis, parsimony and maximum-likelihood method largely agree with previous studies. However, the status of sect. Rhizirideum and sect. Sacculiferum within this subgenus are not consistent with the previous molecular study. Two species whose taxonomic positions have been controversial, A. macrostemon and A. monanthum, are clearly separated from the subg. Rhizirideum.