Molecular systematics of Angelica and allied genera (Apiaceae) from the Hengduan Mountains of China based on nrDNA ITS sequences: phylogenetic affinities and biogeographic implications

Maximum parsimony, maximum likelihood, and Bayesian analyses of nuclear ribosomal DNA internal transcribed spacer sequences were used to infer the phylogenetic affinities and historical biogeography of Angelica and its allies (Apiaceae tribe Selineae), with emphasis on those species of Angelica and Peucedanum endemic to the Hengduan Mountains of south-central China. Results of these analyses corroborate a monophyletic Angelica (Angelica sensu stricto) upon the inclusion of Coelopleurum, Czernaevia, and one of two examined species of Ostericum, but with the exclusion of several species previously attributable to Angelica. Angelica oncosepala and A. likiangensis arise within the genus Heracleum in tribe Tordylieae; the former is recognized under its original name, Heracleum oncosepalum. Angelica sinensis, A. tianmuensis and A. paeoniifolia arise within the Sinodielsia clade of previous circumscription, closely related to Levisticum officinale. Angelica anomala is a sister group to Ostericum grosseserratum in the previously delimited Acronema clade. Angelica apaensis and A. decursiva, taxa whose phylogenetic affinities have previously been controversial, are confirmed within Angelica. Northeast Asia (including Japan, northeast China, Korea and adjacent areas of Russia), Western Europe, and North America are inferred to be ancestral areas of Angelica based on optimal solutions of a dispersal-vicariance analysis, with the Hengduan Mountains likely providing a refugium for Angelica during the latter part of the Tertiary.