A new fern species, Polystichum speluncicola (sect. Haplopolystichum, Dryopteridaceae), is described from a karst cave in southern Guizhou, China. The new species has deltoid-ovate pinnae and subulate microscales with dilated bases on the abaxial lamina surface
(broad-type microscales), characters unknown for any other members of sect. Haplopolystichum s. s. It also has oblanceolate laminae and its pinnae are close-set, subcoriaceous, adaxially lustrous, deltoid-ovate, repand, their acroscopic bases round, and basiscopic bases cuneate, often
forming 20–60-degree angle with the rachis; the basal pinnae are shorter and strongly reflexed. Palynologically, P. speluncicola has cristate sculpturing with numerous spinules on its perispore. A preliminary phylogenetic analysis based on DNA sequences from the trnL–F
intergenic spacer showed that P. speluncicola, together with P. subacutidens, “P. yuanum,” and species of Cyrtomium subser. Balansana, formed an unresolved polytomy. Polystichum speluncicola can easily be distinguished morphologically from
these species by broad-type microscales, deltoid-ovate pinnae, and fewer pairs of pinnae per lamina. Our phylogenetic analysis resolved Cyrtogonellum as paraphyletic in relation to Polystichum sect. Haplopolystichum s. l.