A taxonomic revision of Thuidiaceae (Bryophyta) in Africa and the East African islands

Abstract

A taxonomic revision of the family Thuidiaceae Schimp. for Africa and the east African Islands is presented. Three genera, namely, Pelekium Mitt., Thuidiopsis (Broth.) M. Fleisch. and Thuidium Bruch & Schimp., and 16 species are accepted and revised for the region. The nomenclature, keys to genera and species, descriptions, illustrations and distribution maps are included. Thuidiaceae is one of over 40 families that belong to the Hypnales which is known to contain the most diversity among pleurocarpous mosses. Members of the Thuidiaceae are characterised by gametophytes with attractive, regularly 2- or 3-pinnate branching, presence of paraphyllia on surfaces of stems and branches, dimorphic stem and branch leaves, longitudinally plicate leaves with a single costa, papillose leaf cells, and a hypnoid peristome. Abietinella Müll. Hal., Haplocladium (Müll. Hal.) Müll. Hal., Hylocomiopsis Cardot and Rauiella Reimers are excluded from African Thuidiaceae. Thuidium involvens var. thomeanum Broth. is raised to species status under Pelekium, as Pelekium thomeanum (Broth.) Phephu. Thuidium pseudoinvolvens (Müll. Hal.) A. Jaeger is also transferred to Pelekium and the new combination Pelekium pseudoinvolvens (Müll. Hal.) Phephu is proposed.