Page authors: Don Knoke, David Giblin
Alisma gramineum
grass-leaved water-plantain, narrow-leaf water-plantain

Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Minnesota and Wisconsin.

Habitat: Marshy areas, often in standing water.

Flowers: June-August

Origin: Native

Conservation Status: Not of concern


Aquatic, scapose perennials, the scapes 0.5-3 dm. tall, often exceeded by the leaves.


Leaves all basal, long-petiolate, the blades from narrowly linear to linear-lanceolate or narrowly elliptic, up to 2 cm. broad, often floating when linear.


Flowers in compound, bracteate, terminal panicles, the panicles branches in 2-4 whorles along the axis, the branches with one whorl of pedicles, the upper whorl reduced, the flowers on pedicles from the axis; sepals 3, 2.5 mm. long, greenish, purple-margined, persistent; petals 3, slightly larger than the sepals, reddish- or purplish-tinged; stamens 6, opposite the petals; pistils 10-20 in a single whorl, the sub-terminal style short, persistent.


Achenes sub-orbicular, 2 mm. broad, the style somewhat curled.

Accepted Name:
Alisma gramineum Lej.
Publication: Flore des Environs de Spa. 1: 175. 1811.

Synonyms & Misapplications:
Alisma geyeri Torr. [Abrams]
Alisma gramineum Lej. var. angustissimum (DC.) Hendricks [HC]
Alisma gramineum Lej. var. gramineum [HC]
Additional Resources:

PNW Herbaria: Specimen records of Alisma gramineum in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Alisma gramineum checklist entry.

E-Flora BC: Alisma gramineum atlas page.

CalPhotos: Alisma gramineum photos.

USDA Plants: Alisma gramineum information.

11 photographs:
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