Polystichum tiankengicola (Dryopteridaceae), a New Species from a Karst Sinkhole from Guizhou, China

摘要

A new pteridophyte species, Polystichum tiankengicola Li Bing Zhang, Q. Luo & P. S. Wang (Dryopteridaceae), is described and illustrated from a high-elevational karst sinkhole from Guizhou Province in China. Morphological evidence suggests that P. tiankengicola is a member of series Basigemmifera W. M. Chu & Z. R. He in section Micropolystichum Daigobo, based on the presence of bulbils on rachis and the small habit. Polystichum tiankengicola is unique in series Basigemmifera in having a bulbil at both the base and apex of the rachis. Morphologically, the new species is most similar to P. capillipes (Baker) Diels, also of series Basigemmifera, but beyond the distinctive number of bulbils on the rachis, P. tiankengicola has a truncate lamina apex and its perispores have an echinate sculpture with irregular ridges, in contrast to P. capillipes, which has only one bulbil at the base of the rachis, an acuminate lamina apex, and perispores that have a granular sculpture. Polystichum tiankengicola is found only from the highest elevational, karst sinkhole known in China (2530 m) and is considered to be Critically Endangered (CR), based on IUCN Red List criteria.