(a) : Hydrosere, originating in water (pond, pools, lakes etc.) and starts with the colonization of some phytoplanktons which form the pioneer plant community, and finally terminates into a forest, which is a climax community together with their chief components of vegetation. The various stages together with their components of plant species of a hydrosere are phytoplankton stage, rooted submerged stage, rooted floating stage, reed swamp stage, marsh or sedge meadow stage, woodland stage and climax forest stage. Volvox is phytoplankton, Hydrilla is rooted submerged plant, Pistia is rooted floating plant, Scirpus is reed swamp plant, Lantana is sedge meadow plant and oak is woody tree.