Abstract

Selaginella austrotibetica, a new spikemoss species from China, is described. The species is epipetric and was found on a moss-covered rocky cliff by a riverbank. Morphologically, it is unlike any anisosporophyllous species in the genus Selaginella. However, it resembles species of the S. sanguinolenta group, especially similar to S. sajanensis in gross morphology, except for the characters of strobilus. The molecular phylogenetic analysis clearly showed that S. austrotibetica was nested within the anisosporophyllous species clade, forming a sister relationship with the clade of S. vaginata and S. xipholepis, and distinct from the S. sanguinolenta group, including S. sajanensis. Although S. austrotibetica is sister to the clade of S. vaginata and S. xipholepis, the species can be clearly distinguished by its sparse leaves on branches, dorsal leaves that are broad-ovate, base obtuse to rounded, margin denticulate or very shortly sparsely ciliolate, and leaves that are slightly thick and shiny. Therefore, we described Selaginella austrotibetica as a new species and discuss its phylogenetic relationships within the genus Selaginella.