New record of Pteris esquirolii in Taiwan, with two similar new species, Pteris rugosifolia and Pteris subesquirolii

Three taxa from Taiwan in the Pteris cretica group (Pteridaceae) have extremely wide pinnae, more than 2 cm wide. Leaf and spore morphology complemented with molecular phylogenetic results, indicate these three taxa are new for Taiwan. Compared with similar species in adjacent areas, they are described here as one new record, Pteris esquirolii, and two new species, P. rugosifolia and P. subesquirolii. Pteris rugosifolia has chartaceous and wrinkled laminae, and P. subesquirolii, similar to P. esquirolii, has coriaceous and flat laminae. Furthermore, there are differences in elevation among the three species. A table with morphological diagnostic features of these three species is included, as well as a dichotomous key for the species of the Pteris cretica group species occurring in Taiwan.