Kansas Wildflowers and Grasses - Long-leaf pondweed

LONG-LEAF PONDWEED

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Potamogeton nodosus Poir.

Konza Prairie, Riley County, Kansas

Perennial

Height: Aquatic, submersed and/or floating

Family: Potamogetonaceae - Pondweed Family

Flowering Period: June, July, August, September,October

Stems:

To 60 inches, terete, branched.

Leaves:

Cauline, alternate or nearly opposite distally, simple, both submersed and floating, or floating absent; parallel-veined, glabrous; petiolate. Submersed leaves with stipules pale brown, conspicuous, 1.2 to 3.5 inch, free from blade; petiole .8 to 5 inches; blade linear-lanceolate to elliptic-lanceolate, 3.5 to 8 inches long, .4 to 1 inch wide, veins 7-15, apex acute. Floating leaves with stipules 1.2 to 4 inches; petiole 1.6 to 8 inches; blade elliptic to oblong-elliptic, 1.2 to 4.4 inches ling, .6 to 1.8 inch wide, veins 9--21, base wedge-shaped to rounded, margins entire, apex acute to rounded.

Inflorescences:

Inflorescences spikes, terminal or axillary, emersed, cylindric, .8 to 2.4 inches; peduncles 1.2 to 5.9 inches.

Flowers:

Radially symmetric; tepals 4; stamens 4; pistils 1 or 4.

Fruits:

Reddish brown, obovoid, .1 to .17 inch, beaked, sides rounded, abaxial keel sharp, lateral ridges low.

Habitat:

Usually in shallow water of ponds, lakes, streams, and marshes.

Distribution:

Occurs statewide

Origin:

Native