Gaolejeunea, a new genus from China and new member of subtribe Echinolejeuneinae (Lejeuneaceae, Marchantiophyta)

A narrowly endemic species known only from the type locality in Shangsi Co., Guangxi, as well as a peculiar member of the Chinese Lejeuneaceae, Cheilolejeunea gaoi has previously been treated as a species of Cheilolejeunea. However, the presence of Allorgella-type denticulations formed by two adjacent cells on leaf and underleaf margins, small ovate leaf lobules without distinct teeth, ental hyaline papilla, and finely segmented oil bodies all suggest that it belongs somewhere else. Maximum likelihood, maximum parsimony, and Bayesian analyses of a three marker dataset (nrITS, cpDNA rbcL and trnL-F) derived from 85 accessions of Lejeuneeae and 15 outgroup species revealed that C. gaoi belongs to subtribe Echinolejeuneinae. Based on the results of phylogenetic analyses, combined with morphological data, we suggest here that C. gaoi should be established as a new genus, Gaolejeunea. We strongly recommend in situ or ex situ conservation activity for this species based on the IUCN Red List criteria.