Page authors: Don Knoke, David Giblin
Sparganium emersum
simplestem bur-reed

Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Colorado.

Habitat: Shallow ponds and marshes.

Flowers: June-September

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind


Dioecious, aquatic perennials from rhizomes, the stems erect, 2-4 dm. tall.


Leaves alternate, linear, mostly emersed and erect, sometimes partially submersed or floating, 2-5 dm. long and 6-12 mm. broad, from slightly keeled to triangular, usually expanded and scarious-margined toward the base.


Flowers in globose clusters toward the tip of the main stem; inflorescence simple, with 3-5 pistillate heads below a like number of staminate heads, the pistillate heads up to 3 cm. thick, the lower ones axillary to leaf-like bracts on peduncles up to 12 cm. long; stamens 3-5 with 3-5 minute, chaffy bracts, the filaments long; pistil 1, the stigma linear, 1.5-2 mm. long.


Achenes spindle-shaped, 4-5 mm. long, narrowed to a stylar beak 3-4 mm. long, on a stipe 2.5-3.5 mm. long.

Accepted Name:
Sparganium emersum Rehmann
Publication: Verhandlungen des Naturforschenden Vereins in Brunn. 10: 80. 1872.

Synonyms & Misapplications:
Sparganium angustifolium Michx. ssp. emersum (Rehmann) Brayshaw
Sparganium emersum Rehmann var. emersum [HC]
Sparganium simplex Huds. var. simplex
Additional Resources:

PNW Herbaria: Specimen records of Sparganium emersum in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Sparganium emersum checklist entry

OregonFlora: Sparganium emersum information

E-Flora BC: Sparganium emersum atlas page

CalPhotos: Sparganium emersum photos

33 photographs:
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