Angelica oncosepala and Heracleum yunnanense are synonyms and refer to a species of Tetrataenium (Apiaceae)

Abstract

Heracleum yunnanense Franchet is a poorly known taxon known 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 generic taxonomy of Apiaceae has been largely based on the morphology and anatomy of the 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 well developed 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, as do members of Tetrataenium, but not congruent with species of Heracleum. Phylogenetic analyses using concatenated nuclear ITS and ETS sequences also suggested that A. oncosepala and H. yunnanense should be merged and placed in Tetrataenium. The species name H. yunnanense is the oldest available and Tetrataenium yunnanense (Franch.) Manden is only invalidly published, so we propose the new combination Tetrataenium yunnanense (Franch.) Manden. ex Q. Y. Xiao & X. J. He, and treat A. oncosepala, H. oncosepalum and H. yunnanense as its synonyms.