Page authors: David Giblin, Don Knoke
Agrostis gigantea
black bentgrass

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

Habitat: Disturbed sites, roadsides, edge of agricultural fields, mostly at low elevations.

Flowers: June-September

Origin: Introduced from Eurasia

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind


Rhizomatous perennial, also sometimes stoloniferous, the culms erect to decumbent, often to 12 dm. tall.


Sheaths open; ligules truncate to obtuse, 3-6 mm. long, usually lacerate; blades flat or folded, up to 4 mm. broad.


Inflorescence an open panicle 5-30 cm. long, usually purplish, the branches spreading to ascending, bearing spikelets nearly to the base; spikelets 1-flowered, articulate above the glumes; glumes subequal, 2-2.5 mm. long, acute; lemmas 2/3 to 1/2 as long as the glumes, scabrous on the keel, awnless; palea over 1/2 as long as the lemma; lodicules 2, 0.4 mm. long.



Accepted Name:
Agrostis gigantea Roth
Publication: Tent. Fl. Germ. 1: 31. 1788. 1788.

Synonyms & Misapplications:
Agrostis gigantea Roth var. dispar (Michx.) Philipson
Agrostis nigra With.
Agrostis stolonifera L. ssp. gigantea (Roth) Schübl. & G. Martens
Agrostis stolonifera L. var. major (Gaudin) Farw.
Additional Resources:

PNW Herbaria: Specimen records of Agrostis gigantea in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Agrostis gigantea checklist entry

OregonFlora: Agrostis gigantea information

E-Flora BC: Agrostis gigantea atlas page

CalPhotos: Agrostis gigantea photos

15 photographs:
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