Sphaerocarpales (Marchantiophyta) new to China, with special references to a new species of Sphaerocarpos from Hengduan Mountains

Sphaerocarpales, one of 15 orders in liverworts (Marchantiophyta), is of evolutionary and phylogenetic importance, but has not been recorded in China. Recent expeditions to Hengduan Mountains in China found an interesting liverwort with flask-shaped involucres clearly belonging to Sphaerocarpos, the second largest genus of Sphaerocarpales with nine species. The SEM observations and phylogenetic analyses based on DNA sequences of nuclear ribosomal 26S and two plastid regions (rbcL and psbA-trnH) indicate that the Chinese plant represents a new species described as S. siguniangensis. Our results also reveal that S. texanus known from Africa, America, Europe and Oceania is not monophyletic, suggesting that broader sampling and further analyses of its related species are needed to arrive at a proper understanding of this interesting genus. A new subgenus known only from the U.S.A., Sphaerocarpos subg. Criscarpos, is proposed.