Page authors: Don Knoke, David Giblin
Alisma plantago-aquatica
European water plantain

Distribution: Currently only known from King County in Washington; Alaska, where native, to British Columbia, where also introduced.

Habitat: Marshy areas, sometimes largely submerged.

Flowers: June-September

Origin: Introduced from Eurasia and Alaska

Conservation Status: Not of concern


Scapose perennials, the scapes up to 12 dm. tall, longer than the leaves.


Leaves all basal, long-petiolate, the blades broadly lanceolate to ovate, 5-15 cm. broad, rounded to cordate at the base.


Flowers in much-compounded, bracteate, terminal panicles, the panicles branches in 2-6 whorles along the axis, the lower branches with 2 or more secondary branchlets or pedicles; sepals 3, 3-4 mm. long, greenish; petals 3, strongly pinkish- to purplish-tinged, 4-6 mm. long; stamens 6, opposite the petals; pistils 10-20 in a single whorl; styles 0.7-1.4 mm. long, slender, straight, nearly terminal on the ovary, persistent.


Achenes obovate, 2.5-3 mm. long.

Identification Notes:

Very similar to A. triviale, differing in flower color, and the longer, slender, straight style terminal on the ovary.

Accepted Name:
Alisma plantago-aquatica L.
Publication: Sp. Pl. 1: 342. 1753.

Synonyms & Misapplications:
Alisma plantago-aquatica L. var. plantago-aquatica [HC]
Additional Resources:

PNW Herbaria: Specimen records of Alisma plantago-aquatica in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Alisma plantago-aquatica checklist entry.

E-Flora BC: Alisma plantago-aquatica atlas page.

CalPhotos: Alisma plantago-aquatica photos.

USDA Plants: Alisma plantago-aquatica information.

1 photographs:
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