1. Chloris verticillata Nutt. (showy windmill grass)

Pl. 142 i, j; Map 576

Plants perennial, the stems sometimes appearing stoloniferous. Flowering stems 8–40 cm long, mostly erect from horizontal bases, strongly flattened. Leaves mostly near the base of the flowering stems. Leaf sheaths strongly keeled on the back. Leaf blades 1–12 cm long, 1.5–4.0 mm wide. Inflorescences with 6–20 spikes, these 4–15 cm long, mostly spreading, arranged in 2–5 whorls along the axis, with the numerous spikelets not or only slightly overlapping. Lower glume 1.8–3.0 mm long. Upper glume 3.0–4.5 mm long. Fertile lemma with the body 2–3 mm long, broadly ovate, pointed at the tip and with an awn 4–9 mm long, inconspicuously short‑hairy on the margins and midnerve. Sterile lemmas with the body 1–2 mm long, the awn 3.5–5.0 mm long. 2n=40, 63. May–October.

Widely scattered in Missouri (Iowa to Colorado south to Louisiana and Arizona). Upland prairies; also lawns, roadsides, railroads, and open, disturbed areas.

In the western states, this species is an indicator of overgrazed rangeland. At maturity, the inflorescence often becomes detached from the rest of the plant at the base and is dispersed by wind as a “tumbleweed.”