2.

Setaria glauca (L.) P. Beauv. (yellow foxtail)

Pl. 175 c, d; Map 703

S. lutescens (Weigel) F.T. Hubb.

S. pumila (Poir.) Roem. & Schult.

Plants annual, with soft bases, without rhizomes. Flowering stems 20–80(–130) cm long, often somewhat flattened, glabrous. Leaf sheaths usually somewhat keeled, glabrous along the margins and on the surface, the ligule 0.5–2.0 mm long. Leaf blades 3–30 cm long, 4–12 mm wide, usually loosely twisted or spiraled, glabrous or roughened, sometimes with sparse, pustular‑based hairs near the base on the upper surface, often somewhat glaucous. Inflorescences 3–15 cm long, erect or curved to somewhat nodding toward the tip, the very short branches reduced to clusters of spikelets and the inflorescence thus appearing as a cylindrical spike, the main axis with short, soft, upwardly pointing hairs, the spikelets subtended by 5–20 yellow bristles, these 3–8 mm long. Spikelets 2.8–3.5 mm long, disarticulating below the glumes. Lower glume 0.9–1.8 mm long. Upper glume 1.4–2.4 mm long. Lowermost floret usually staminate, 2.0–3.2 mm long. Fertile floret with the lemma 2.0–3.1 mm long, with noticeable, fine cross‑wrinkles on the surface. Anthers 0.9–1.4 mm long. 2n=36, 72. June–October.

Introduced; scattered to common throughout the state (native of Europe; introduced and weedy nearly worldwide). Margins and disturbed openings of mesic upland forests, upland prairies, and banks of streams and rivers; also pastures, fallow fields, crop fields, levees, lawns, roadsides, railroads, and open, disturbed areas.