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Pond water-starwort (Callitriche stagnalis)
Small, delicate plants usually found in shallow water and loosely rooted to the bottom.
Other names for this plant include:
- Common names: common starwort, common water-starwort, water chickweed
- Found in shallow waters and may threaten biological diversity by shading and crowding out other species.
Classification in Wisconsin: Caution. This is a non-regulated category.
Species Assessment Groups (SAG) were assembled to recommend a legal classification for each species considered for NR 40. The recommendation for pond water-starwort was based upon this literature review developed by the department.
Leaves: Opposite; narrow and submersed (up to 10mm wide) with one rounded leaf tip are sometimes present; oval or spoon-shaped floating leaves are up to 10 mm wide; joined by tiny ridges at the base.
Flowers: Tiny; lack sepals and petals; located at the leaf bases on minute stalks; 2-4 tiny whitish bracts emerge from the flower base
Fruits & seeds: Small, located at the leaf bases; four compartments, each containing one seed; oval, 1.2-1.8mm long, 1.2-1.7mm wide, narrow margin all around (wing); bracts at base.
Roots: Fibrous, from plant base or sprouting from stem joints.
Similar species: May be confused with other starworts; to be sure of identification to species, the surfaces of mature fruit need to be examined under 10-20x magnification.
See the reported locations of pond water-starwort.
Do you know of additional pond water-starwort populations? Send us a report.
Mechanical: Dredging can deepen a waterbody to a depth where Pond Water-Starwort cannot receive enough light for growth. However, dredging is expensive, particularly if the sediments of a waterbody are contaminated, and require disposal. Cutting Pond-Water Starwort can be viable by the plant fragments must be removed to prevent regrowth. Shading has been successful at impeding growth of Pond Water-Starwort. However, shading an entire waterbody or large areas of a waterbody would be difficult and expensive.
View pond water-starwort pictures in our photo gallery!