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Water Starwort

Callitriche spp.

Water starwort is a bay grass with bright green, egg-shaped leaves that float on the surface of the water. It grows in quiet fresh waters throughout the Chesapeake Bay watershed.

Appearance:

Water starwort has bright green, oval- or egg-shaped leaves on the upper part of its stem and straight leaves on the lower, submerged part of its stem. Two leaves grow at each joint on the stem.

Habitat:

Grows in quiet, non-tidal fresh waters such as streams, lakes and ditches, and is occasionally found in small, shallow tidal freshwater creeks and rivers. Egg-shaped leaves float in clusters on the water’s surface.

Range:

Found in tidal and non-tidal fresh waters throughout the Chesapeake Bay watershed.

Predators:

Ducks feed on the leaves and seeds.

Reproduction and Life Cycle:

Water starwort reproduces both sexually and asexually. It flowers from July to September, forming numerous seeds.

Other Facts:

• Water starwort provides habitat for fish and aquatic insects.
• There are four species of water starwort that grow in North America, but they are so similar that you need a microscope to distinguish them.

Sources and Additional Information:

• Underwater Grasses in Chesapeake Bay & Mid-Atlantic Coastal Waters by Maryland Sea Grant
• Bay Grass Key: Water Starwort – Maryland Department of Natural Resources
• Weed Identification Guide: Water Starwort – Virginia Tech

Places:

• Susquehanna River Water Trail – Lower Section – Harrisburg, Pennsylvania to Havre de Grace, Maryland
• Potomac River Water Trail – Washington, D.C. to Point Lookout, Maryland