Page authors: Don Knoke, David Giblin
Ammannia robusta
western ammania, grand redstem

Distribution: Occurring east of the Cascades crest in Washington chiefly along the Columbia River; British Columbia to California, east to the Great Lakes region and midwestern U.S.

Habitat: Wet places, often where alkaline.

Flowers: May-June

Origin: Native

Conservation Status: Threatened in Washington (WANHP)


Simple to branched annual, the stem 5-40 cm. tall.


Leaves opposite, entire, oblong to oblong-lanceolate, 2-4 cm. long and 2-8 mm. broad, cordate-clasping at base.


Flowers 1-5 in cymes in the leaf axils, sessile; calyx strongly 8-ribbed and 4-angled, bell-shaped, 2-3 mm. long, with small teeth in the sinuses; petals short-lived, purplish, 1 mm. long; stamens 4; style slightly exerted, 1-1.5 mm. long; stigma discoid.


Capsule 4-celled, membranous, globose, 4 mm. long.

Accepted Name:
Ammannia robusta Heer & Regel
Publication: Index Seminum [Zuerich] adn. 1. 1842.

Synonyms & Misapplications:
Ammannia coccinea Rottb. ssp. robusta (Heer & Regel) Koehne
Additional Resources:

PNW Herbaria: Specimen records of Ammannia robusta in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Ammannia robusta checklist entry.

E-Flora BC: Ammannia robusta atlas page.

CalPhotos: Ammannia robusta photos.

USDA Plants: Ammannia robusta information.

11 photographs:
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