The Genus Delphinium L. From The Hengduan Mountains Region In Southwestern China: Taxonomy And Cytology

Delphinium L. (Ranunculaceae) is a large genus of 300-400 species widely distributed in the temperate regions of the Northern Hemisphere. This genus is most richly represented in China, with 173 species already recorded, and in geographical distribution mostly restricted in the Hengduan Mountains region of southwestern China, one of the biodiversity hotspots in the world.Based on literature survey, and both herbarium and field observations, the variation pattern within and between populations of all the major morphological characters of the Chinese Delphinium species, particularly those from the Hengduan Mountains region, was studied, and the taxonomic values of the characters were preliminarily evaluated. The results show that the root shape, the degree of leaf division, the pubescence of the plant, particularly of the inflorescence axis and of the pedicel, the bracteole position and shape, the color of the staminode, the shape of the upper sepal, the carpel number, and the seed morphology, are the most constant and hence most reliable diagnostic taxonomic characters in the genus. It is noteworthy that the characters are very often not well correlated with each other, and that even the most constant characters sometimes exhibit certain variations. A single character, therefore, is often of different taxonomic values for the circumscription of taxa of different categories and for the taxonomic treatment in different groups. As such, characters or character combinations as many as possible should be used in the course of conducting taxonomic treatment of the genus.