J Syst Evol ›› 1996, Vol. 34 ›› Issue (5): 505-530.

• Research Articles • Previous Articles     Next Articles

A Phylogenetic Analysis of Gentiana (Gentianaceae)

Ho Ting-nong, Liu Shang-wu, Lu Xue-feng   

  • Published:1996-09-10

Abstract: A cladistic study was undertaken to make the infrageneric classification and to evaluate the phylogenetic relationships in the genus Gentiana. As a monophyletic group,Gentiana is based on three synapomorphies and includes 23 series and 10 monotypic Sections.Two genera,Tripterospermum and Crawfurdia, were selected as the outgroups.Most character complexes were surveyed and 61 informative characters from morphology,palynology and cytology were used for this study.The analysis resulted in 51 equally parsimonious cladograms and the one with the lowest f-value of 0.213 was selected as the base for discussing cladistic classification and making cladistic analysis.Results of the cladistic classification support most of the current systematic classification of Gentiana,With main differences in the circumscription of some sections (e.g.,Frigida,Isomeria and Chondrophylla). In the cladogram,Centiana was first split into two clades,the perennial clade and the annual clade.In the perennial clade,Sect. Pneumonanthe emerged earlier and is the most primitive taxon in this genus. Two subclades,the Asian subclade and the European subclade,came out after Sect.Pneumonanthe. The Asian subclade includes eight sections (Cruciata,Otophora,Frigida,Microsperma,Monopodiae,Kudoa,Phyllocalyx and Isomeria).The first two sections which form the Cruciata-branch diverged at a low level,especially Sect. Cruciata is also a primitive taxon of the genus Gentiana.The remaining sections which constitute the Frigida-branch are more advanced.The European subclade includes Sect.Gentiana,Sect.Ciminalis and Sect.Calathianae. This subclade is regarded as a relatively isolated and specialized one in Gentiane.The annual clade consists of two sections (Dolichocarpa and Chondrophylla),of which Sect. Chondrophylla is a more advanced taxon. In addition, Sect. Stenogyne was considered to be of a hybrid origin between the two genera Tripterospermum and Gentiana with some characters of its parents.A strict consensus tree summariesthe points of agreement in all the 51 equally parsimonious trees; The phylogenetic relationships of the sections and series in the genus Gentiana are also strongly supported by this consensus tree.

Key words: Gentiana, Phylogeny, Cladistic classification, Cladistic analysis