SHORT COMMUNICATION A Preliminary Survey of Bryophytes in the Central Province of Sri Lanka

Bryophytes possess a key position in land plant evolution and hold the link between green algal ancestors and vascular plants. Bryophytes comprise the most diverse and species rich group of land plants after flowering plants. The most recent classification includes bryophytes in three phyla: Marchantiophyta (liverworts), Bryophyta (mosses) and Anthocerotophyta (hornworts). Bryophyte flora of Sri Lanka is poorly researched and does not contribute much to its biodiversity figures. Therefore, a preliminary survey was carried out in the Central Province of Sri Lanka to aid future bryological research in the country. This on-going survey has identified 15 liverworts, 27 mosses and 2 hornworts, with 12 new species records in Sri Lanka. DOI: http://dx.doi.org/10.4038/cjsbs.v42i1.5901 Ceylon Journal of Science ( Bio. Sci. ) 42 (1): 67-72, 2013


INTRODUCTION
Bryophytes (commonly referred to as 'mosses') are frequently found in damp shady places, along riverbanks, edges of ponds and lakes, on tree trunks and even on manmade habitats like roofs and walls. These tend to form tufts or close mats. They do not produce flowers, seeds or fruits and also do not possess a proper vascular system composed of a xylem and phloem. After flowering plants, bryophytes are the most diverse and species-rich lineage of embryophytes (Mishler, 2001;Renzaglia et al., 2007;Wellman and Gray, 2000). This diverse group is also referred to as non-vascular land plants or nonvascular embryophytes. Extant bryophytes comprise more than 15,000 described species worldwide (Beike and Rensing, 2010;Vanderpoorten and Goffinet, 2009).
Traditionally, 'bryophytes' included three morphologically distinct groups based on the type of gametophyte; i.e., liverworts, mosses and hornworts. According to the most recent classification scheme proposed by Crandall-Stotler et al. (2009), the three groups of bryophytes (liverworts, mosses and hornworts) are recognized as three phyla; Bryophyta (mosses), Marchantiophyta (liverworts) and Anthocerotophyta (hornworts), based on both morphological and molecular data. As the only extant group of land plants with a dominant gametophytic generation, they share many fundamental structural features and display unifying and innovative reproductive characters. Therefore, despite their paraphyletic position, the three phyla are still frequently categorized together in a single group, the 'Bryophytes' (Crandall-Stotler, 1980;Schofield, 1985). Further, bryophytes lack a proper cuticle or roots, the uptake of water is mainly from the ambient humidity. Therefore, more than any other organism, bryophytes are highly sensitive to climate change. Due to deforestation and climatic changes over the years, the bryophyte flora of the world may have changed drastically and many endemics may have gone extinct. However, no proper records are currently available, especially in developing countries like Sri Lanka.
Explorations on the Sri Lankan bryophyte flora began in the 19 th Century and many contributions to the field were made mainly by British bryologists and explorers including George Gardner (1812 -1849), G. H. K. Thwaites (1812 -1882), W. Mitten (1819 -1906), and C. C. Townsend (O'Shea, 2003 and references therein). All major publications on Sri Lankan bryophytes up to date are based on the collections made by Gardner and Thwaites and few sporadic collections made afterwards. The existing checklists on bryophytes up to date are limited (Abeywickrama and Jansen, 1978;O'Shea, 2003) and do not represent the entire group. The literature-based checklist produced by Abeywickrama and Jansen (1978) included all the taxa known to have published at the time: 174 genera and 569 species of mosses, 60 genera and 183 species of liverworts and 03 genera and 06 species of hornworts. An updated checklist was published by O'Shea (2002) with 560 moss species. A literature-based study by O'Shea (2003) recorded a high endemicity (11%) for mosses. However, no accurate evaluation or study has been carried out so far to check the endemicity of liverworts and hornworts.
Since the available checklists do not include earlier synonyms for taxon names or their original publications, several taxa are listed under more than one name while some taxon names are no longer accepted (O'Shea, 2003). Apart from the few sporadic collections, no proper explorations or systematic studies on Sri Lankan bryophytes have been carried out. Therefore, there is a great need for field explorations and well documented collections, based on the updated recent classifications. However, a major impediment for such explorations is that much of the existing literature and checklists are old and the collections are scattered in herbaria in several continents. These highlight the importance of systematic field explorations, subsequent taxonomic identification and documentation of bryophytes of the country.
Therefore, a preliminary survey of bryophytes in the Central Province was undertaken with the view of initiating systematic bryological studies in Sri Lanka.

MATERIALS AND METHODS
The preliminary survey of bryophytes was carried out in Kandy and Nuwara Eliya Districts of the Central Province of Sri Lanka. Samples were collected from different habitats including natural forests, agro-forests, urban ecosystems and road sides and stored in paper packets as described by Schofield (1985

RESULTS AND DISCUSSION
In the present survey, a total of 44 bryophytes were identified to their species/generic level, which included 15 liverworts, 27 mosses and 2 hornwort species. The details of species identified in each group are listed below (Boxes 1, 2 and 3). Recent changes in taxonomic circumscriptions of familial, generic and/or specific ranks are described in the list where necessary as 'notes'.
Ten families were encountered under the Phylum Marchantiophyta (liverworts): 6 complex thalloid families: Aytoniaceae (2), Cyathodiaceae (2) Results of the current study revealed 12 new species records in Sri Lanka which include 2 complex thalloid liverworts, 1 leafy liverwort, 1 simple thalloid liverwort and 10 mosses. The new species records are indicated with a delta (' ∆ ') mark (Boxes 1, 2 and 3). The newly recorded species are currently being examined further to describe their taxonomic and biogeographic affinities.  Note: The genus Phaeoceros which was earlier included in the family Anthocerotaceae is now placed in the family Notothyladaceae based on molecular phylogenies, detailed morphological and ultrastructural analyses (Renzaglia et al., 2009).

CONCLUSION
The current survey revealed 15 liverworts, 27 mosses and 2 hornworts, with 12 new species records in Sri Lanka. This highlights the importance of implementing conservation measures to protect the rich bryophyte flora of the country. The survey is continued with repeated field explorations to collect and identify more species. Further studies on characterization of species and verification of their geographical distribution and status are also being conducted. The lack of a 'Bryophyte Flora' or any established classification system/taxonomic keys for genera and species of liverworts, mosses and hornworts of Sri Lanka is a major impediment to conduct research on bryophyte flora of the country and therefore, systematic updates and a classification system for the Sri Lankan bryophyte flora need to be developed.