Page author: Kevin Armitano
Poa trivialis
rough-stalk blue grass

Flowers: May - July

Origin: Introduced

Conservation Status: Not of concern


Perennial, short-lived; loosely to densely tufted, usually weakly stoloniferous.


Basal branching intra-vaginal; culms 25-120 cm, decumbent to erect, sometimes trailing and rooting at nodes, terete or weakly compressed; nodes terete or slightly compressed, 1-3 exserted; sheaths closed for 1/3 to 1/2 of length, compressed, often densely scabrous, bases of basal sheaths glabrous, distal sheath lengths 0.5-4 times blade lengths; collars smooth or scabrous, glabrous; ligules 3-10 mm, scabrous, acute to acuminate; blades 1-5 mm wide, flat, lax, soft, sparsely scabrous over the veins, margins scabrous, apices narrowly bow-shaped.


Spikelets 2.3-3.5 mm, lengths 3 times widths, laterally compressed; florets 2-4, bisexual; rachilla internodes smooth or muriculate; glumes distinctly keeled, keels scabrous; lower glumes subulate to narrowly lanceolate, curved, 1-veined, distinctly shorter than the lowest lemmas; calluses webbed, hirsute, hairs over 2/3 the lemma length; lemmas 2.3-3.5 mm, lanceolate, distinctly keeled, keels usually sparsely puberulent along 3/5 of length, marginal veins usually glabrous, infrequently the proximal 1/4 softly puberulent, intercostal regions smooth, glabrous, upper lemmas sometimes glabrous, lateral veins prominent, margins glabrous, apices acute; palea keels smooth, muriculate, tuberculate, or minutely scabrous; anthers 1.3-2 mm.


Caryopses 1-4 mm, ellipsoid, usually shallowly ventrally grooved, solid; hilum sub-basal, round or oval, to 1/6 length of the caryopses.

Accepted Name:
Poa trivialis L.
Publication: Sp. Pl. 1: 67. 1753.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Poa trivialis in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Poa trivialis checklist entry.

E-Flora BC: Poa trivialis atlas page.

CalPhotos: Poa trivialis photos.

USDA Plants: Poa trivialis information.

8 photographs:
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