摘要：A cladistic analysis of the medicinal plant Taxus , using the sequences of one chloroplast ( trnS – trnQ spacer) and three nuclear taxadiene synthase ( TS ), 10-deacetylbaccatin III-10β- O -acetyltransferase ( DBAT ), and 18S rDNA ) molecular markers, was carried out by distance, parsimony, likelihood, and Bayesian methods. Three of the four New World species ( T. brevifolia , T. floridana and T. globosa ) form a well-supported clade, whereas T. canadensis initially branches—appearing distantly related to both Old World taxa and New World species. In Asia, Taxus chinensis , T. mairei , T. sumatrana and T. wallichiana cluster together and are sister to a clade containing T. baccata and T. contorta . Taxus yunnanensis is more closely related to T. wallichiana than to four other Taxus species in our study from China; T. contorta is closer to the Euro-Mediterranean T. baccata than to the Asian species. This study provides a genetic method for authentication of economically important Taxus species and proposes a robust phylogenetic hypothesis for the genus. Using trnS – trnQ spacer sequences, we were able to distinguish T. mairei from all other species of Taxus .
