Distribution: Occurring chiefly east of the Cascades crest in central Washington; central Washington to southern Oregon, east to Idaho and Montana.
Habitat: Moist meadows and subalpine slopes, usually in forest edge or understory.
Flowers: June-August
Origin: Native
Growth Duration: Perennial
Conservation Status: Not of concern
Pollination: Wind
Perennial with short, stout rhizomes, the culms 6-15 dm. tall, glabrous.
Sheaths open; ligules 6-15 mm. long, irregularly jagged; blades of the culm leaves flat, up to 12 cm. long; blades of the sterile shoots nearly twice as long and half as wide.
Inflorescence a compact panicle 8-16 cm. long, often interrupted below; spikelets 1-flowered; glumes 5.5-7 mm. long; lemma slightly shorter than the glumes, with an awn attached about mid-length, the awn twisted and bent, exceeding the glumes by about 5 mm.; palea subequal to the lemma, the rachilla prolonged behind the palea 2-4 mm., strongly bearded; callus very lightly bearded.
Publication: Contributions from the United States National Herbarium 3(1): 83. 1892. 1892.
PNW Herbaria: Specimen records of Calamagrostis tweedyi in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Calamagrostis tweedyi checklist entry.
OregonFlora: Calamagrostis tweedyi information.
E-Flora BC: Calamagrostis tweedyi atlas page.
CalPhotos: Calamagrostis tweedyi photos.
USDA Plants: Calamagrostis tweedyi information.
