Ming-He Li

Tree of life for the genera of Chinese vascular plants

We reconstructed a phylogenetic tree of Chinese vascular plants (Tracheophyta) using sequences of the chloroplast genes atpB, matK, ndhF, and rbcL and mitochondrial matR. We produced a matrix comprising 6098 species and including 13 695 DNA sequences, of which 1803 were newly generated. Our taxonomic sampling spanned 3114 genera representing 323 families of Chinese vascular plants, covering more than 93% of all genera known from China. The comprehensive large phylogeny supports most relationships among and within families recognized by recent molecular phylogenetic studies for lycophytes, ferns (monilophytes), gymnosperms, and angiosperms. For angiosperms, most families in Angiosperm Phylogeny Group IV are supported as monophyletic, except for a paraphyletic Dipterocarpaceae and Santalaceae. The infrafamilial relationships of several large families and monophyly of some large genera are well supported by our dense taxonomic sampling. Our results showed that two species of Eberhardtia are sister to a clade formed by all other taxa of Sapotaceae, except Sarcosperma. We have made our phylogeny of Chinese vascular plants publically available for the creation of subtrees via SoTree (http://www.darwintree.cn/flora/index.shtml), an automated phylogeny assembly tool for ecologists.

A molecular phylogeny of Chinese orchids

We estimated the molecular phylogenetic relationships of the Chinese members of the family Orchidaceae. Within the Tree of Life for the Genera of Chinese Vascular Plants using atpB, rbcL, matK, ndhF, and matR, the currently delimited subfamilies, tribes, and subtribes are highly supported as monophyletic except for the perplexing Epidendroideae. Five genes (rbcL, matK, psaB, ycf1, and Xdh), which are more universally used in Orchidaceae, were further analyzed to reconstruct the phylogeny of Epidendroideae. The reconstructed trees were in strong agreement and showed significant support for the tribal and subtribal clades. Based on the highly supported circumscription and arrangement of the suprageneric levels in the Tree of Life and reconstructed trees, we have proposed a new phylogenetic classification of Chinese Orchidaceae that includes five subfamilies, 17 tribes, and 21 subtribes.

A new myco-heterotrophic genus, Yunorchis, and the molecular phylogenetic relationships of the tribe Calypsoeae (Epidendroideae, Orchidaceae) inferred from plastid and nuclear DNA sequences.

We identified a new holomycotrophic orchid that is related to the myco-heterotrophic Calypsoeae. Because chloroplast genes are primarily lacking or are highly divergent, key morphological characters are either reduced or lost from many myco-heterotrophs, and the phylogenetic relationships of weakly supported paraphyletic Calypsoeae within Epidendroideae have been poorly understood in previous molecular systematic studies. Using chloroplast rbcL, psaB, and matK and nuclear Xdh and ITS sequences, we determined the circumscription and systematic positions of the new orchid and the tribe. The results indicate that the epidendroid taxa include most of the clades that are successively sister to the grade of clades representing previously recognized tribes. Calypsoeae comprising four well-supported clades with 12 genera (except for the previous temporarily placed Wullschlaegelia) is supported as a monophyletic and sister clade to Epidendreae (excluding Coeliinae). The new orchid is nested in Calypsoeae and is a sister to Dactylostalix and/or Calypso. This new holomycotrophic orchid presents a subumbel inflorescence that grows underground, and flower with a long pedicel reputing the ground to open and two fragments at the base of the hook, which are obviously morphologically different from those of Calypsoeae. To accommodate this species in the current generic circumscription, a new genus Yunorchis was created.