Page authors: Don Knoke, David Giblin
Potamogeton zosteriformis
eel-grass pondweed, flat-stem pondweed
Specimens
Photos

Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana, and much of north central and northeast United States and adjacent Canada.

Habitat: Lakes, ponds and streams.

Flowers: June-August

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind

Description:
General:

Aquatic, herbaceous perennials from slender rhizomes, the stems flattened and somewhat winged, 2-3 mm. broad, constricted at the nodes, freely branched, up to 6 dm. long.

Leaves:

Leaves all submersed, linear, up to 20 cm. long and 3-5 mm. broad, not at all clasping; stipules free of the leaf blade, 1-3 cm. long, whitish, firm.

Flowers:

Flowers in dense spikes 1-2.5 cm. long; peduncles stout, flattened, up to10 cm. long; perianth of 4 clawed segments, each with an upturned, oval blade; stamens 4, fused with the claws; pistils 4, sessile.

Fruits:

Flowers in dense spikes 1-2.5 cm. long; peduncles stout, flattened, up to10 cm. long; perianth of 4 clawed segments, each with an upturned, oval blade; stamens 4, fused with the claws; pistils 4, sessile.

Accepted Name:
Potamogeton zosteriformis Fernald
Publication: Memoirs of the american academy of arts and science. n.s. 17:36. 1932.

Synonyms & Misapplications:
Potamogeton compressus L., misapplied
Additional Resources:

PNW Herbaria: Specimen records of Potamogeton zosteriformis in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Potamogeton zosteriformis checklist entry

OregonFlora: Potamogeton zosteriformis information

E-Flora BC: Potamogeton zosteriformis atlas page

CalPhotos: Potamogeton zosteriformis photos

7 photographs:
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