curly leaf pondweed

Potamogeton crispus L.

Description from Invasive.org

Appearance: Potamogeton crispus is a perennial, submerged, aquatic herb that is native to Eurasia.
Foliage: Leaves are sessile, oblong, stiff, 1.6-3.9 in. (4-10 cm) long, 0.2-0.4 in. (5-10 mm) wide, translucent and have noticeably curly margins (resemble lasagna noodles).
Flowers: Flowering occurs in the summer to early fall, when emergent flowers develop. Flowers are brown, inconspicuous and wind pollinated.
Fruit: Fruits are flat with a pointed beak and are 0.16-0.24 in. (4-6 mm) long. The seed do not seem to be viable. In the midsummer plants form turions (vegetative buds), from which new growth starts in fall or winter.
Ecological Threat: Potamogeton crispus tolerates fresh or slightly brackish water and can grow in shallow, deep, still or flowing water. Plants can grow in clear or turbid water, but are mostly shade intolerant. The method of introduction is unclear and it may have been introduced as a hitchhiker on boats, through the aquarium trade, or accidently when stock from a fish hatchery was released. It was first collected in 1860.

Resources

Global Invasive Species Database - Invasive Species Specialist Group

Selected Images from Invasive.org

View All Images at Invasive.org

Plant(s)
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Feature(s) Turion
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Foliage
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

Foliage
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Additional Resolutions & Image Usage

Infestation
Chris Evans, University of Illinois, Bugwood.org
Additional Resolutions & Image Usage

Plant(s) Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 1: 81.
USDA NRCS PLANTS Database , USDA NRCS PLANTS Database, Bugwood.org
Additional Resolutions & Image Usage