Present paper deals with 8 samples of water fern-Ceratopteris thalictroides (L.) Brongn. growing in the fresh water lakes of Indian Botanic Garden, Shibpur, Howrah and in nearby areas inundated by different factory wastes containing hydrocarbons, saponins, mercury residues and various heavy metals in addition to acidic and alkaline residues.
Biology of the water fern including spore production, fertility, germination etc. have been studied under control (IBG lakes) and field stress conditions. It is observed that environmental and pollution stress cause severe alteration in the life cycle of this aquatic fern affecting spore production rate, fertility percentage and germination. It is also observed that presence of humus in the soil, salinity and pH of the water also affect the biology and phenotypic plasticity of this water fern. Present observation will be very much helpful in further studies on the biology of the aquatic plants.