Algae
Algae exists in many forms including microscopic (planktonic), while others are thin and stringy or cotton ball texture (filamentous), and some are large and resembles higher plants but without true roots, stems, or leaves (muskgrass/chara/starry stonewort).  Algae reproduces by means of spores, cell division, and fragmentation.

Floating Plants
Plants with leaves that float on the surface and are rooted on the bottom.  Free-floating surface plants with a well developed root system or obtain their nutrients directly from the water through cell walls.  Water is critical for support of the plant or its leaves.

Emergents
Plants that grow above the water in shallow areas of ponds, lakes, and rivers or in saturated soils.  These plants are generally rigid and are not dependent on water for support.

Submersed Plants
Plants are generally rooted at the bottom and are completely underwater.  Flowers, if present, may extend above the water surface.