Selaginella wangpeishanii (Selaginellaceae), a new lycophyte from a limestone cave in Guizhou, China

Selaginella wangpeishanii, a new species of the lycophyte genus Selaginella (Selaginellaceae) from a limestone cave in southern Guizhou, China is described and illustrated. The new species is different from any species in the genus known so far in China by having some ultimate branches bearing microphylls in ascending order of trophophylls, sporophylls or sporophyll-like microphylls, and trophophylls (TST arrangement of microphylls). Morphologically, S. wangpeishanii is most similar to S. gebaueriana, but is distinct by smaller plants and serrulate margins of lateral trophophylls. Selaginella wangpeishanii is currently known only from a single population and is considered to be Critically Endangered (CR), based on IUCN Red List criteria.