Often, they will begin growth attached to some substrate and eventually break loose to float upon the surface in mats. More advanced forms of algae such as Chara, also known as muskgrass because of its pungent odor, resemble rooted weeds. They commonly grow in thick beds off the pond bottom in relatively clear water. Older plants become gray-green to whitish in color due to gritty calcium deposits on their outer surfaces. Basic aquatic weed groupings are differentiated by location in the environment and growth form.
Emergent plants grow along the shoreline or in shallow, marshy areas.
Examples include cattails, rushes, sedges, and arrowheads. These are found on the water surface, their leaves lying parallel or protruding from the water. Rooted species are generally found in shallow areas, whereas free-floating types may be distributed throughout. Examples include water lilies, water hyacinth, watershield, duckweed, and watermeal. Submerged plants are found underwater and may be either rooted or lying on the bottom.