Taxonomic treatment of the family Polytrichaceae Schwägr. in Sri Lanka

Abstract

Sri Lanka harbors a rich diversity of mosses (Phylum Bryophyta) with 561 species, 185 genera and 55 families. According to the checklist of mosses of Sri Lanka by O’Shea (2002), Polytrichaceae Schwagr. represents one of the most species-rich families comprising of two genera (Atrichum and Pogonatum) with 12 species. Available details on species and genera of the family are limited to mere literature based lists; no taxonomic keys, descriptions or monographs for the recorded species are available. The present study was carried out to investigate the species diversity and prepare a taxonomic treatment of the Family Polytrichaceae in Sri Lanka. Polytrichaceae is unique among other moss families by the formation of an epiphragm from the columella, presence of photosynthetic lamellae on upper leaf surface and multicellular peristome appearing single with 32 to 64 teeth. Specimens were collected from all possible geographic localities including; NuwaraEliya, Thispane, Horton Plains, Adam’s Peak, Piduruthalagala, Badulla, Kanneliya Rain Forest, Riverston, Deanston, Corbert’s Gap, Deraniyagla, Elkaduwa, Gannoruwa, Mahakanda, Loolecondera, Kurunegala, Jaffna, Anuradhapura, Dambulla and Galle. Specimens were thoroughly examined for morphological and anatomical characters using, dissecting and light microscopes and identified up to specific/generic level using taxonomic keys, descriptions and monographs. The specimens collected during the study represented two genera (Atrichum and Pogonatum) genera and seven species of the family Polytrichaceae in Sri Lanka: Atrichum crispulum Schimp. Ex Besch., Pogonatum aloides (Hedw.) P. Beauv., P. marginatum Mitt., P. microstomum (Schwagr.) Brid., P. neesii (C. Mull.) Dozy, P. subtortile (C. Mull.) Jaeg. and P. urnigerum (Hedw.) P. Beauv. A taxonomic key to Sri Lankan Polytrichaceae and descriptions along with illustrations for all the species identified are presented. Further investigations are made to explore all recorded species by O’Shea (2002) and to trace their distribution patterns within the island.