|Water-stargrass (Heteranthera dubia)||Water-stargrass is a fully submerged perennial that can reach 1.45 m long, bending at the water surface. The stems may be creeping, upward-growing or floating and are often tangled; they are highly branched, especially at the crown of the plant, forming a vegetative cover just below the water surface. Water-stargrass often grows in tufts or small colonies in which other plant species become entangled; the resulting clusters can be very dense.In areas where fish are abundant, water-stargrass provides adequate shelter against predators. It is also a favourite food for ducks and other waterfowl.
Water-stargrass reproduces very effectively by means of small shoots that grow from the rhizome (underground stem) and from nodes on the old stems.
Its preference for sand and gravel soils suggests that water-stargrass has minimal nutrient requirements or that it feeds mainly through its leaves. In clear water, it can grow at depths varying from 1 to 3 meters.
Water-stargrass grows only in mesotrophic to eutrophic waters (i.e., waters containing medium to high nutrient levels).