Disentangling the taxonomy and morphology of Ectropothecium (Bryophyta: Hypnaceae s.l .) with comments on its generic relationships, and Neoptychophyllum , a new name for the genus Ptychophyllum

Abstract

Ectropothecium is a genus of Hypnaceae, consisting of epiphytic or lithophytic species that are mainly distributed in tropical and subtropical forests. With 233 currently accepted species, the genus has one of the most difficult taxonomies among pleurocarpous mosses. Delimitation of Ectropothecium has been challenging because of morphological convergence between closely related genera within the Hypnaceae, namely Hypnum , Isopterygium , Taxiphyllum , and Vesicularia . Redefining the generic limits is based on reassessment of seven critically important morphological features, i.e., branching pattern, pseudoparaphyllium type, leaf shape, laminal cell surface, alar cell formation, capsule size, and exothecial cell walls. Microscopic images of morphological and anatomical important features are used to show generic characteristics. The five closely related genera are morphologically distinct, but oftentimes difficult to separate apart without considering several features at the same time. The generic delineation of Ectropothecium is provided. Neoptychophyllum (Hypnaceae), a new name is proposed for the genus Ptychophyllum , an illegitimate homonym and a previous generic synonym of Ectropothecium .