Poa annua L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Tufted annual with few–several decumbent to ascending or seldom erect culms to 3 dm, sometimes rooting at the lower nodes; sheaths loose; blades soft, 2–3 mm wide; infl ovoid, 2–8 cm, with few ascending branches bearing rather crowded spikelets above the middle; spikelets green, 3–5 mm, 3–6-fld; glumes broadly lanceolate, acute, scarious-margined, indistinctly veined, the first 1.5–2.4 mm, the second 1.8–2.8 mm; lemmas thin, elliptic, 5-veined, obtuse, ± hairy on the veins only, not webbed, the lowest one 2.4–3.4 mm; anthers 0.8–1 mm; 2n=14, 28. Native of Eurasia; abundant in moist soil nearly throughout the U.S. and n. to Lab. and Alas.; often a lawn-weed.