Abstract: The present paper was communicated with the morpho-taxonomic description of three diatom taxa belonging to the order Pennales of the class Bacillariophyceae namely Fragilariopsis cylindrus, Achnanthidium lineare and Rhopalodia gibba var. ventricosa. Among them, the former species is rare in occurrence within freshwater ecosystem while the latter two species are found sparsely to abundant in pond, water reservoirs and other types of aquatic bodies. The limnological characteristics that supported their occurrences in water bodies were recorded and found to be congenial for their growth. The pH of water in studied aquatic bodies was observed alkaline and acceptable quantity of phosphate, nitrate-nitrogen and silica along with other physico-chemical parameters of waters were also noted. The above mentioned all three diatom taxa are new taxonomic reports from this district of West Bengal, India.
Fig.: A. Fragilariopsis cylindrus; B. Achnanthidium lineare; C-D. Rhopalodia gibba var. ventricosa (valve & girdle views).