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Plantwise Technical Factsheet

curlyleaf pondweed (Potamogeton crispus)

Description

P. crispus is an herbaceous, submersed aquatic species that typically grows with stem up to 1m long. Its sessile, linear leaves are light to dark-green. They are typically from 1.2-9 cm long, 4-10 mm wide and are spirally arranged on flattened cauline stems. Leaves are homophyllous, often undulate, with obtuse apices and 3-5 veins. Margins are finely serrate. Lacunae are conspicuous and occur in rows of 2-5 along the midrib of the leaf. Stipules are not fused to the leaf and persistent, though inconspicuous. Leaves and stem are lax; the plant is either entirely submersed or nearly entirely submersed with some leaves floating at the surface. Nodal glands in this species are entirely absent. Inflorescences are unbranched and emersed, generally terminal (Flora of North America Editorial Committee, 1993). Flowers are tiny, with four petal-like lobes on spikes 1-3 cm long on stalks up to 7 cm long (Washington State Department of Ecology, 2008). Sessile reddish-brown single-seededĀ fruits are unkeeled and measure 6 x 2.5 mm. Fruits have a small recurved beak that measures 2-3 mm. Embryo has full spiral. Short, bur-like hardened turions, in which internode length is extremely shortened, measure 1.3-3 by ~2 cm, are common and can be either apical or axillary (Flora of North America Editorial Committee, 1993; USACE, 2002).

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