Morphological cladistic analysis of Ligusticum (Umbelliferae) in China

Ligusticum L. consists of over 60 species which are widely distributed in Eurasia and North America, with 40 of these species found in China. This paper attempts to carry out a cladistic analysis on all 40 Chinese Ligusticum species and several species from the allies of Ligusticum, such as Selinum L, Conioselinum Fisch., and Cnidium Cuss. using their floral and vegetative morphological characters. The cladistic analysis does not support Ligusticum as a monophyletic genus. Instead, the 40 species are divided into five clades according to the MP (maximum parsimony) tree. With discussion revolving on each of the clades, Tilingia Regel is suggested to be restored, Ligusicopsis Leute is confirmed not to be a natural genus, and some useful clues about the relationship between Ligusticum, Selinum, and Conioselinum are discovered. The taxonomic significance and evolutionary trends of bracteoles and pollen grain characters are discussed.