NOT NATIVE TO MAINE - INVASIVE
Habitat: Curly-leaf pondweed is found in the submersed plant community. Generally preferring soft sediments, it grows in waters that are shallow or deep, still or flowing. Curly-leaf thrives where many other aquatic plants do not, for example in waters that are shaded, disturbed, polluted or turbid.
Description: Curly-leaf pondweed has submersed leaves only. (Some pondweeds have two distinct leaf types: submersed leaves and floating leaves.) Slightly flattened stems emerge from slender rhizomes and sprouting turions, often branching profusely as they grow, giving the plants a bushy appearance. Mature stems may be several meters in length. The leaves of this plant are key to its identification. Though the leaves share characteristics with some native pondweeds, they also have three distinct characteristics that set this plant apart from any of its native look alikes (see comparison table). Stipules, when visible, (they disintegrate early in the plantís growth cycle) are slightly joined to the stem at the leaf base and 4 to 10 mm long. Flower spikes appear above the surface of the water from June through September. The small flowers are tightly arranged at the end of a slender (often curving) stalk measuring about 7 cm in length. The fruits have a prominent cone-shaped beak and a bumpy, crown-like ridge. (The shape resembles the profile of a crested woodpecker.) Turions form in the leaf axils during the growing season. The turions are hard but flexible (like stiff plastic) and typically 1 to 2 cm long.
Origin and U.S. Range: Curly-leaf pondweed is native to Eurasia. Introduced to the United States some time during the mid 1800s, it has since spread to almost every state in the country. In addition to spread by natural causes and recreational activity, curly leaf pondweed has been planted intentionally for waterfowl and wildlife habitat, and possibly has been spread as a contaminant in water used to transport fish and fish eggs to hatcheries. Curly-leaf was first confirmed in a small pond in southern Maine in 2004 and is currently present in the nearby states of New Hampshire, Massachusetts, Vermont, Connecticut, New York and Rhode Island.
Annual Cycle: Curly-leaf pondweed, an aquatic perennial, is adapted to growing in cool conditions. Plants sprout from rhizomes and turions in the late fall and grow through the winter, reaching maturity relatively early in the season (late spring through early summer). Flowers and turions are produced during the growing season and the plants generally begin breaking up by mid-July. The turions scatter with the plant fragments and drop to the sediments, where they lie dormant until the water begins to cool again in the fall. In addition to propagation by turions and creeping rhizomes, curly-leaf pondweed produces seeds. Little is known, however, regarding the importance of seeds in the spread and propagation of this plant.
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Water Quality Monitoring
Aquatic Invasive Monitoring
Maine Volunteer Lake Monitoring Program
24 Maple Hill Road, Auburn, ME 04210
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