2016 Mentors and Projects

Associate Curator

Using molecular and morphological data to discover cryptic speciation in the holly fern genus Polystichum (Dryopteridaceae) in limestone caves in Asia. Libing Zhang has been at MBG since 2006; he is an associate curator with expertise in the taxonomy and molecular systematics of ferns, and has worked with students from high school and graduate levels. Polystichum subgenus Haplopolystichum is one of two subgenera of Polystichum, a nearly cosmopolitan genus that is perhaps the third largest genus of ferns belonging to the largest fern family, Dryopteridaceae. Species of subg. Haplopolystichum are diminutive lithophytes; almost all have 1-pinnate leaves. They are endemic to East Asia, including its continental islands. The highest diversity is on the limestone terrains of southern China; a few species reach the neighboring Himalaya, Japan, Korea, Myanmar, the Philippines, the Russian Far East, Thailand, and Vietnam. There are ca. 90 species currently known in the subgenus. Of these, 15 are cave-entrance endemics in karst terrains, all but one of which are confined to single caves. These species differ in pinna shape and pinna-edge characters as well as in spore surface patterns. Material has been collected of other populations in other cave entrances that do not correspond to known species; there may be up to 25 such species. This project will use both morphological and molecular characters to verify the status of new species and define how to recognize them. A participating student can work in the lab, generating molecular systematic data, and also study the morphology of this group of ferns.