Contributions to a Monograph of the Lejeuneaceae Subfamily Ptychanthoideae

Lejeuneaceae include species with or without underleaves. Those with underleaves (the majority) have traditionally been classified (e.g. Spruce 1884) into “Lejeuneaceae Holostipae” (underleaves undivided) and “Lejeuneaceae Schizostipae” (underleaves bifid). This system has now become obsolete and has been replaced by a more natural classification into subfamilies, based on several gametophytic as well as sporophytic characters (Schuster 1984, Grolle 1983). The current subfamily system of Lejeuneaceae is shown in Table I, which also lists the genera containing holostipous species. From this table it becomes apparent that holostipous Lejeuneaceae are a clearly unnatural, polyphyletic group, comprising taxa of 5 different subfamilies. Two subfamilies and 34 genera are purely holostipous, including most notably the Ptychanthoideae (23 genera). Notwithstanding their unnaturalness, “Holostipae” and “Schizostipae” are still recognised in practical Lejeuneaceae taxonomy as the most distinct groups. The present paper focuses on the holostipous members of the family and presents an up-to-date generic key emphasizing vegetative characters, to facilitate identification of sterile material. In addition, references to the main literature on individual genera and species are provided.