Plants annual, 5–65 cm tall.
Leaves sheaths glabrous; the uppermost sheaths sometimes inflated; ligules 2.5–16 mm; blades 1–20 cm × 1–7 mm.
Inflorescences narrowly ellipsoid, sometimes lobed, 1–17 cm; pedicels absent or to 0.2 mm; stipes 0.1–0.2 mm.
Glumes 1–2.7 mm, ciliate, minutely hairy throughout, largest hairs restricted to the lower half; tips rounded, lobed, lobes 0.1–0.2 mm, 10% or less as long as the glume body, awned; glume awns 4–10 mm, yellowish.
Lemmas 0.5–1.5 mm, glabrous, awned; lemma awns 0.5–1(4.5)mm.
Anthers 0.2–1 mm.
2n=28, 35.
Disturbed wet sites, ditches, roadsides, often on alkaline soils. 0–1700m. All ecoregions except Casc. CA, ID, NV, WA; throughout most of North America; worldwide. Exotic.
A hybrid of P. monspeliensis and Agrostis stolonifera (× Agropogon lutosus) has been found in Oregon. It differs from P. monspeliensis in having more tapered, short-awned glumes and lemmas with subterminal awns. Unlike A. stolonifera, its spikelets are on short stipes.