Taxonomic revision of Angelica oncosepala and Heracleum yunnanense

5 October 2017

Xiao, Qun-Ying; Yu, Yan; Xie, Deng-Feng; Guo, Xian-Lin; He, Xingjin

Heracleum yunnanense Franchet is a poorly known taxon recorded only from the type collection. Angelica oncosepala Handel-Mazzetti was originally described as a member of Angelica and later placed in Heracleum as Heracleum oncosepalum (Handel-Mazzetti) Pimenov & Kljuykov. The classification of genera of Apiaceae has been largely based on the morphology and anatomy of fruit. In this study, various characters of A. oncosepala are found to be identical with H. yunnanense. In addition, we discovered that H. yunnanense and A. oncosepala have better developed and narrowly keeled dorsal and intermediate ribs, broadly winged marginal ribs, 1 vittae in dorsal valleculae, 2 in lateral valleculae, 4 on commissure and linear vittae, corresponding to Tetrataenium very well, not to Heracleum. Phylogenetic analyses using concatenated nuclear ITS and ETS sequences also concluded that A. oncosepala and H. yunnanense should be merged and placed in Tetrataenium. The species name H. yunnanense was earliest described for the taxon and Tetrataenium yunnanense (Franch.) Manden was invalidly published, so we proposed the new nomenclatural combination Tetrataenium yunnanense (Franch.) Manden. ex Q. Y. Xiao & X. J. He, and treated A. oncosepala, H. oncosepalum and H. yunnanense as its new synonyms.