A revision of Dryopteris sect. Diclisodon (Dryopteridaceae) based on morphological and molecular evidence with description of a new species

Dryopteris sect. Diclisodon is a small section of ferns with about 12 species mainly distributed in East Asia. Here, we carried out morphological and phylogenetic analyses of this section. A new species from southwest China, D. gaoligongensis, is described and illustrated. Dryopteris gaoligongensis resembles D. indonesiana and D. sparsa, but differs by having a creeping rhizome and large 4-pinnate fronds. We also show that D. glabrior Ching & Z.Y. Liu is a distinct species; however, because it is a later homonym of D. glabrior Copel., it should be renamed D. renchangiana. We conclude that a species previously known as D. nitidula, also an illegitimate homonym, should be recognized with a new name, D. sinonepalensis. We resolve the phylogenetic position of D. yoroii as sister to other sampled species of D. sect. Diclisodon. Our phylogenetic analyses confirm the distinctiveness of D. gaoligongensis, D. renchangiana, and D. sinonepalensis. A key to species of D. sect. Diclisodon in China is provided.