Abstract
Mastigolejeunea is morphologically close to Thysananthus and the separation of these two genera has long been controversial. The relationship between Mastigolejeunea and Thysananthus is assessed based on Bayesian inference and maximum likelihood analyses of plastid psbA-trnH, trnG and trnL-F, and nuclear ITS. Mastigolejeunea was resolved as sister to Thysananthus with moderate support, but M. calcarata was nested in Thysananthus subsect. Anguiformes and M. florea was resolved in Spruceanthus. Because diagnostic morphological features separating Mastigolejeunea from Thysananthus are lacking, Mastigolejeunea is treated as a subgenus of Thysananthus. The latter group becomes the second largest genus of Lejeuneaceae subfam. Ptychanthoideae with 30 species, and is one of the largest genera of liverworts that has been monographed worldwide.