DIVERSITY OF PTERIDOPHYTES IN BIRBHUM DISTRICT, WEST BENGAL

摘要

The district Birbhum situated between 23°32'30" and 24°35'0" north latitude and 087°5'25" and 088°1'40" east latitude, and about 4,545 square kilometers (1,755 sq M) in area. It lies on the southern segment of West Bengal, India and a part of Rarhregion. Pteridophyte diversity was studied by employing quadrate method and quantitative as well as qualitative ecology was studied. A total twenty pteridophytes were collected from three subdivisions of the district namely, Bolpur, Rampurhat and Suri.The distribution of species was calculated from the abundance to percentage frequency ratio, showed that three species namely Adiantum vhilippense, Thelypteris interrupta and Salvinia cucullata were distributed randomly in the district. Distribution of Azolla pinnata and Salvinia molesta within the district is contagious whereas the rest fifteen (15) species were distributed regularly. The Shanon- Weaver index is inversely proportional to dominance index and the corresponding values were 0.087, 0.24 and0.14 in Bolpur, Suri and Rampurhat sub-division respectively. The Similarity index (037) and Dissimilarity index (0.63) revealed that though the species assemblage is lesser throughout the district but the variation in species was present.