Phylogenetic and phenetic relationships of the fern genus Lepisorus (J. Smith) Ching (Polypodiaceae) and related genera

Abstract

Lepisorus (J. Sm.) Ching s.l. is a fern genus that mostly occurs in the old world. So far its taxonomic circumscription remains unclear because sometimes it included or excluded its related taxa (i.e. Paragramma and Platygyria). Also, sometimes the Platygyria was merged to the genus Neocheiropteris. This research mainly aims to clarify the circumscriptions of the genus Lepisorus, Paragramma and Platygyria. In phenetic approach, cluster and discriminant analyses have been performed based on 53 morphological and anatomical characters and phylogenetic analysis was carried out based on 33 morphological and anatomical characters. The result from both cluster and canonical discriminant analyses showed that the specimens were separated into three groups: (1) specimens of Neocheiropteris ensata and N. palmatopedta, (2) specimens of Platygyria (3) specimens of Lepisorus s.s. N. normalis and Paragramma. Therefore based on phenetic analyses, the Platygyria should be treated as distinct taxon, and N. normalis and Paragramma should be merged to the genus Lepisorus. In addition, the Neocheiropteris should be treated as a distinct genus. In phylogenetic approach, the result showed that the analysis based on these characters cannot be used to assess the circumscriptions of these genera because most clades on phylogenetic tree was poorly supported by bootstrap analysis. Therefore, the Platygyria should be treated as a distinct genus while the circumscription of the Lepisorus should be include N. normalis and Paragramma and the rest of Neocheiropteris should be treated as a distinct genus based on the results obtained from phenetic analyzes.