Taxonomic revision of Aconitum (Ranunculaceae) from Sichuan, China

Taxonomy of the genus Aconitum L. from Sichuan, SW China, was revised. Based on literature survey, extensive field and herbarium observations, morphological variations shown within and between populations in the genus from Sichuan were studied. The taxonomic significance of the major gross morphological characters was evaluated. The degree of leaf division, the shape of upper sepal and pedicel pubescence are found to be the most reliable diagnostic characters for the circumscription of species, although sometimes even these characters are variable within and between populations of the same species and change greatly with environmental conditions. The petal and seed morphology can provide characters useful for infrageneric division. Forty-six species and 11 varieties of Aconitum are recognized from Sichuan. Two species (A. potaninii Kom. and A. limprichtii Hand.-Mazz.) and one variety (A. handelianum var. laxipilosum Hand.-Mazz.) are numerated as dubious taxa because of the unavailability of their type specimens for examination. Twenty-nine species and 22 varieties are reduced to synonymies. Two new combinations, A. legendrei var. albovillosum (Chen & Liu) Y. Luo & Q. E. Yang and A. liljestrandii var. fangianum (W. T. Wang) Y. Luo & Q. E. Yang, are proposed. Two species, A. delavayi Franch. and A. nagarum Stapf, are newly recorded from Sichuan. Three species, A. tatsienense Finet & Gagnep., A. henryi Pritz. and A. refractum (Finet & Gagnep.) Hand.-Mazz. are lectotypified. The identity of A. tongolense Ulbr. and A. refractum was clarified. Description, distribution and a key to the subgenera, series and species are given.