Scanning electron microscopy (SEM) is the most modern technique for plankton research. The present paper deals with the taxonomy and morphology of some rare and endangered planktonic chlorophytes in relation to scanning electron microscopy. Water samples from the distinct water body of the Sundarbans have been concentrated and examined by scanning electron microscopy. A total of 45 species, of which 17 species of Scenedesmaceae, 10 species each of Hydrodictyaceae and Desmidiaceae, five species of Chlorococcaceae, two species of Selenastraceae and only one species of Chlorellaceae were recorded from the study site. Some species were recorded as new and rare from the study area. About 18 species including nine extremely rare, seven occasional, six frequent, four sporadic and one abundant was recorded in the present study. A detailed taxonomic description with line drawings is also included in the present communication. © Satpati & Pal 2019.