A Revised Framework of Dryopteris subg. Nothoperanema (Dryopteridaceae) Inferred from Phylogenetic Evidence, with Descriptions of Two New Sections

Dryopteris subgenus Nothoperanema (Dryopteridaceae) includes sections Acrophorus, Diacalpe, Nothoperanema, and Peranema. Phylogenetic relationships among these sections and their relationship to sect. Dryopsis (genus Dryopteris subgenus Erythrovariae, Dryopteridaceae) are unclear. Additionally, previous phylogenetic work has not included Stenolepia, which has been suggested as an important relative of Peranema based on morphology. In this study, we examined phylogenetic relationships within subgenus Nothoperanema by including Stenolepia and utilizing six plastid regions (similar to 5,500 characters). Our inferred phylogeny revealed that sect. Dryopsis is not monophyletic. The Nothoperanema clade is highly supported, and includes sect. Acrophorus, sect. Diacalpe, sect. Nothoperanema, sect. Peranema, certain Dryopsis species, and Stenolepia. By re-examining diagnostic morphological characters, we establish and describe two new sections under subgenus Nothoperanema: sect. Shiehia and sect. Stenolepia. This revision accommodates new species transferred from sects. Dryopsis and Stenolepia, and makes subgenus Nothoperanema and each of its sections natural groups. Finally, we provide a table with morphological comparisons and a key to sections.