Burke: Potamogeton nodosus

	Potamogeton nodosus
	loddon's pondweed, long-leaved pondweed
Habit	Aquatic, herbaceous perennials from slender rhizomes, the stems sub-terete, sparingly branched, up to 2 m. long.
Leaves	Leaves alternate, the submersed leaves with petioles 2-10 cm. long, the blades lanceolate-elliptic, 10-20 cm. long and 1-2 cm. broad, thin; floating leaves leathery, long-petiolate, elliptic, 5-12 cm long and 2-4 cm. broad; stipules 4-8 cm. long.
Flowers	Flowers perfect, in densely-flowered spikes with up to 15 whorles, 2-6 cm. long; peduncles thicker than the stems; perianth of 4 clawed segments, each with an upturned, oval blade; stamens 4, fused with the claws; pistils 4, sessile.
Fruits	Achenes obovoid, 3-4 mm. long, with a sharp dorsal keel and prominent lateral keels.

	Potamogeton nodosus
Flowering time	June-August
Habitat	Shallow to rather deep water.
Distribution	Occurring on both sides of the Cascades crest in Washington; British Columbia to Mexico; east over most of the United States to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]
Origin	Native
Conservation status	Not of concern
Sibling taxa	P. alpinus, P. amplifolius, P. berchtoldii, P. crispus, P. epihydrus, P. fibrillosus, P. foliosus, P. friesii, P. gramineus, P. illinoensis, P. natans, P. obtusifolius, P. praelongus, P. pusillus, P. richardsonii, P. robbinsii, P. strictifolius, P. zosteriformis
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Potamogeton nodosus

loddon's pondweed, long-leaved pondweed

Habit

Aquatic, herbaceous perennials from slender rhizomes, the stems sub-terete, sparingly branched, up to 2 m. long.

Leaves

Leaves alternate, the submersed leaves with petioles 2-10 cm. long, the blades lanceolate-elliptic, 10-20 cm. long and 1-2 cm. broad, thin; floating leaves leathery, long-petiolate, elliptic, 5-12 cm long and 2-4 cm. broad;

stipules 4-8 cm. long.

Flowers

Flowers perfect, in densely-flowered spikes with up to 15 whorles, 2-6 cm. long;

peduncles thicker than the stems;

perianth of 4 clawed segments, each with an upturned, oval blade;

stamens 4, fused with the claws;

pistils 4, sessile.

Fruits

Achenes obovoid, 3-4 mm. long, with a sharp dorsal keel and prominent lateral keels.