18. Panicum miliaceum L. (broomcorn millet, proso millet, common millet)
Pl. 169
f–h; Map 679
Plants annual, forming tufts. Flowering stems 10–100 cm
long, relatively stout, more or less circular in cross‑section, glabrous
or hairy. Leaves scattered along the stems. Leaf sheaths rounded on the back,
hairy, the hairs sometimes with pustular bases, the ligule 1–3 mm long, a
membrane with a fringe of hairs along the margin. Leaf blades 5–40 cm long,
6–20 mm wide, relatively soft, ascending to spreading or arched, sparsely to
densely hairy, flat. Inflorescences 4–25 cm long, less than 1/2 as long as the
entire flowering stem, 3–4 times as long as wide, remaining attached to the
flowering stem at maturity, not becoming a “tumbleweed,” usually somewhat
arched or drooping, the primary branches ascending, not spikelike, rebranched 1
or more times, the spikelets not appearing 1‑sided, clustered along the
branches, short‑stalked, not curved or angled with respect to their
stalks. Spikelets 4.5–6.0 mm long, elliptic‑ovate in outline, narrowed or
tapered to a short, sharp point at the tip, glabrous. Lower glume 2.3–3.6 mm
long, about 1/2 as long as the rest of the spikelet, broadly ovate, sharply
pointed at the tip, 5‑ or 7‑nerved. Upper glume
3.8–5.8 mm long, elliptic, narrowed or tapered to a short, sharp point at the
tip, 7–11‑nerved. Lowermost floret sterile and with a short palea,
the lemma 4.5–6.0 mm long, elliptic, 7‑ or 9(–15)‑nerved.
Fertile floret 2.7–3.7 mm long, elliptic, bluntly pointed at the tip. Anthers 1.6–2.0 mm long. Fruits 2.5–3.5 mm
long, narrowly elliptic to elliptic in outline, straw‑colored to light
brown at maturity. 2n=36. June–November.
Introduced, uncommon and widely
scattered in the state (native of Europe; escaped from cultivation in the
eastern U.S. west to Colorado). Fallow fields, railroads, and open,
disturbed areas.
A weedy form with somewhat longer stems and more open
inflorescences has been called var. spontaneum (Kit.) Tzvelev.
This minor variant has not been recorded from Missouri yet. The species is sometimes
cultivated for forage in the northern United States.