2012年后新成立研究组知识库

Polystichum (Dryopteridaceae) is a cosmopolitan fern genus known for its rich species diversity, with its primary diversity center in eastern Asia. In this study, we describe a novel species, Polystichum cretaceum, discovered in Napo County, Baise City, Guangxi Zhuang Autonomous Region, China. This species is distinguished by its dwarf habit, fronds simple or 1pinnate (pinnae 2-4 pairs), pilose or glabrous surface, and fenestrate perispores. This new species resembles P. fraxinellum but differs by having oval pinnae with entire margins and free veins, while P. fraxinellum has ovate-lanceolate pinnae with slightly recurved margins and anastomosing veins. Phylogenetic analysis suggests a close relationship between P. cretaceum and P. minimum. However, P. minimum differs in having obliquely ovate lateral pinnae with shallowly incised-toothed margins and acuminate apices.