[Karyotype analysis and its systematic implications of Pterocypsela formosana and P. elata]

Pterocypsela is a very important traditional Chinese medicine from the tribe Cichorieae of Asteraceae. Mitotic chromosome numbers and karyotypes are reported for P. formosana and P. elata from Hunan and Hubei province, China. The former is new and the latter provide confirmation of previous reference. All P. taxa are diploidy with 2n = 18 and their basic number is tentatively suggested as x = 9. Karyotype of Pterocypsela is 2A and P. formosana with a karyotype formula of 2n = 2x = 18 = 4m + 14sm, and 2n = 2x = 18 = 2m + 8sm +8st for P. elata. It is the first time to report the AI value for Pterocypsela in this paper. Cytological data of chromosomal numbers and karyotypes were used to discuss the close relationships of the Pterocypsela genus and the taxonomy of the medicinal plants.