Abstract
The fern genus Pseudocyclosorus (Thelypteridaceae) from China and the Pan-Himalaya region is revised based on morphological study. Reduced basal pinnae, angles between costule and costae, and glands/hairs on abaxial surfaces/indusia are considered as the most diagnostic morphological characters for species delimitation. Genus Trigonospora was excluded from genus Pseudocyclosorus. This segregation is supported by multiple morphological features. Eight species were recognized here, namely Pseudocyclosorus tylodes, P. pseudofalcilobus, P. falcilobus, P. subochthodes, P. stramineus, P. ornatipes, P. esquirolii and P. canus. Twenty-one names were reduced as new synonyms. One name (P. duclouxii) was considered a dubious species. A key to these eight species, their descriptions, spore morphology and distribution map of each species are given.
Pseudocyclosorus stramineus was a long overlooked species, which has always been misidentified as other similar species, and was wrongly reduced as a synonym of P. duclouxii. Here based on morphology characters, the identity of P. stramineus as a species was reclaimed. A more detailed description with photographs and illustrations, and its whole distribution range are given here.