Callitriche palustris (formerly known as Callitriche verna)

Common Water Starwort

NATIVE TO MAINE

Habitat: Common water starwort grows in the submersed and emergent plant communities. This plant is generally found in cool, quiet waters or along muddy shores, preferring muddy or sandy substrates.

Description: Common water starwort has fine stems that are 10 to 20 cm long. The submersed leaves are opposite, and arranged in pairs or in groups of three. The delicate leaves are simple, entire and variable in appearance. The submersed leaves tend to be pale green and linear. The upper leaves are more rounded (5mm wide) and crowded at the tip, forming a rosette that floats on the surface. The flowers grow in the axils of the leaves and produce very small capsule-like fruits (1 to 1.4mm). The fruits are distinctive, having narrow wings along shallow grooves and surface pits arranged in vertical rows. This plant is very similar in appearance to large water starwort. The fruits may be needed to distinguish between the two species.

Range: Common water starwort is a native plant species. It may be found throughout much of the U.S.

Annual Cycle: Common water starwort is an annual that reproduces by seed and stem fragments. Because the plant is adapted to cool water, growth begins early and flowers bloom in early summer. Seeds are mature by mid to late summer.

Value in the Aquatic Community: Ducks and other waterfowl feed upon the stems and fruits of common water starwort. Colonies of this plant provide food and shelter for fish.

Look Alikes: Brazilian elodea, hydrilla, common waterweed, and large water starwort.