Page author: Don Knoke
Arrhenatherum elatius
tall oatgrass

Distribution: Introduced more commonly west of the Cascades, British Columbia south to California, east to Idaho and Montana.

Habitat: Meadows and pastures.

Flowers: May - July

Origin: Introduced

Growth Duration: Perennial

Conservation Status: Not of concern


Tall perennials, the culms hollow, 8-15 dm. tall, the bases enlarged, often rooting at the first few nodes, but erect, not rhizomatous.


Sheaths open, smooth; ligules 1-2 mm. long, truncate; blades 8-10 mm. broad, scabrous and often with long hairs.


Inflorescence a narrow, shining panicle 1-3 dm. long; spikelets 2- flowered, the lower flower staminate, the upper perfect; articulation above the glume; glumes papery, keeled, unequal, the first 5-7 mm. long, 1-nerved, the second 7-10 mm. long, 3-nerved; lemmas bearded on the callus, 7-nerved, that of the first flower with a stout, twisted, strongly-bent awn 10-20 mm. long, attached about mid-length; lemma of the second flower with a subterminal, straight awn up to 6 mm. long; paleas about equal to the lemmas; rachilla prolonged as a bristle behind the upper palea; stamens 3; lodicules 2, linear, 2.5-3.5 mm. long.



Accepted Name:
Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl

Synonyms & Misapplications:
Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl var. biaristatum (Peterm.) Peterm.
Avena elatior L.
ssp. bulbosum – bulbous oatgrass
ssp. elatius – bulbous oatgrass
Additional Resources:

PNW Herbaria: Specimen records of Arrhenatherum elatius in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Arrhenatherum elatius checklist entry.

E-Flora BC: Arrhenatherum elatius atlas page.

CalPhotos: Arrhenatherum elatius photos.

USDA Plants: Arrhenatherum elatius information.

42 photographs:
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