9. Sporobolus pyramidatus (Lam.) Hitchc. (whorled dropseed)

Pl. 154 h; Map 631

S. argutus (Nees) Kunth

Plants perennial (often short‑lived), forming tufts. Flowering stems 10–60 cm long. Leaves mostly basal. Leaf sheaths glabrous or occasionally with a few long hairs at the tip, the ligule 0.5–1.0 mm long. Leaf blades 1–20 cm long, 2–5 mm wide, usually flat, roughened and sometimes also sparsely hairy at the base of the upper surface and margins. Inflorescences 3–10(–15) cm long, terminal, open panicles, ovate to broadly triangular in outline, mostly free from the subtending leaf sheath, the lowermost branches whorled, often somewhat sticky. Spikelets 1.2–2.0 mm long, the glumes noticeably unequal in length, the lower glume 1/4–1/2 as long as the upper glume. Lower glume 0.3–0.9 mm long, lanceolate to narrowly triangular, narrowed to a sharp point at the tip. Upper glume 1.2–2.0 mm long, about as long as the floret, elliptic‑ovate. Lemma 1.2–2.0 mm long, elliptic‑ovate, 1‑nerved, sharply pointed at the tip, glabrous. Paleas usually slightly shorter than the lemmas. Anthers 0.3–0.5 mm long. Fruits 0.6–0.9 mm long, broadly oblong in outline, tan to pale orange. 2n=24, 30, 36, 54. July–September.

Introduced, known from a single historical collection from Jackson County ( Florida to Arizona north to Kansas and Colorado, introduced sporadically in the northeastern U.S.; Mexico, Central America, South America, Caribbean Islands). Dry, open, disturbed areas.