Page authors: Don Knoke, David Giblin
Najas flexilis
slender naias, nodding water-nymph, slender water-nymph

Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Montana, Colorado, Utah, and Arizona, east across the northern Great Plains to the Great Lakes region and eastern North America.

Habitat: Fresh to slightly brackish water.

Flowers: April-August

Origin: Native

Growth Duration: Annual

Conservation Status: Not of concern


Monoecious, submersed annual, the slender, branching stems 3-6 dm. long and scarcely 1 mm. thick.


Leaves opposite, 1-3 cm. long and 0.5 mm. broad, the base expanded for 3-5 mm. and somewhat sheathing, the blade tapered almost from the base to a long, slender point.


Flowers tiny, in the axils of leaves clustered toward the branch tips; staminate flowers few, a single stamen enclosed in a transparent bract; pistillate flowers naked, the pistil 1, the stigmas 2-4, sessile, elongate.


Achene spindle-shaped, 3 mm. long, completely filled by the single seed.

Accepted Name:
Najas flexilis (Willd.) Rostk. & W.L.E. Schmidt
Publication: Flora Sedinensis. 382. 1824.

Synonyms & Misapplications:
Caulinia flexilis Willd.
Najas caespitosus (Maguire) Reveal
Additional Resources:

PNW Herbaria: Specimen records of Najas flexilis in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Najas flexilis checklist entry.

E-Flora BC: Najas flexilis atlas page.

CalPhotos: Najas flexilis photos.

USDA Plants: Najas flexilis information.

11 photographs:
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