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Potamogeton nodosus - (image 1 of 5)

Taxonomy

Family: Potamogetonaceae

Habitat

Streams, lakes, ditches, often in alkaline water.

Associates

Distribution

Widespread, nearly cosmopolitan.

Morphology

Perennial aquatic with floating leaves; stems 1-2 m long, simple or with a few branches. Submersed leaves thin, narrowly lanceolate to linear, to 30 cm long and 2.5 cm wide, 7-15 veins, acute, gradually tapering to a petiole 2-12 cm long; floating leaves elliptic, to 13 cm long and 4 cm wide, more or less acute; petioles to 20 cm; stipules axillary, free, to 10 cm long, attenuate to obtuse; peduncles to 12 cm long, stout, often thicker than the stem; spikes cylindric, dense, to 5 cm. Fruits somewhat obovoid, to 4 mm, with a sharp, narrow, often tuberculate dorsal keel and occasionally with 2 low ridges on the sides.

Notes

Flowers July.

Wetland indicator: Obligate

One of the more common pondweeds.

References

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Second Ed.

The New York Botanical Garden. Bronx, NY

Swink, F. and G. Wilhelm. 1994. Plants of the Chicago Region.
Indiana Academy of Science. The Morton Arboretum. Lisle, Illinois.

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