Page authors: Don Knoke, David Giblin
Glyceria grandis
American mannagrass, reed mannagrass
Specimens
Photos

Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.

Habitat: Sloughs, damp meadows and stream borders.

Flowers: June-August

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind

Description:
General:

Strongly rhizomatous perennial, the culms 9-16 dm. tall.

Leaves:

Sheaths smooth, completely closed, or open up to 1 cm.; ligules 4-9 mm. long, obtuse, entire; blades flat, firm, 6-15 mm. broad.

Flowers:

Inflorescence a loose, open panicle 2-3.5 dm. long, the branches spreading, numerous; spikelets loosely 5- to 6-flowered, oblong in outline; glumes papery, lanceolate, 1-nerved, the first about 1.6-1.7 mm. long, the second, 2.5 mm. long; lemmas 2.5-2.7 mm. long, purplish, blunt, prominently 7-nerved to the scarious upper margin, the nerves non-convergent; paleas about equal to the lemmas, abruptly notched; stamens 3, or occasionally 2.

Accepted Name:
Glyceria grandis S. Watson
Publication: Manual (Gray), ed. 6. 667. 1890.

Synonyms & Misapplications:
Glyceria maxima (Hartm.) Holmb. ssp. grandis (S. Watson) Hultén
Glyceria maxima (Hartm.) Holmb. var. americana (Torr.) B. Boivin
Panicularia grandis (S. Watson) Nash
Infraspecies:
Additional Resources:

PNW Herbaria: Specimen records of Glyceria grandis in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Glyceria grandis checklist entry.

OregonFlora: Glyceria grandis information.

E-Flora BC: Glyceria grandis atlas page.

CalPhotos: Glyceria grandis photos.

USDA Plants: Glyceria grandis information.

28 photographs:
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