Crested greenhead sedge

Cyperus metzii (Hochstetter ex Steudel) Mattfeld & Kükenthal

Plants annual, cespitose, not rhizomatous. Culms 5–35 cm, smooth. Leaves flat, 5–30 cm × 1.5–2 mm. Inflorescences: spike 1, subglobose, 6–10 mm diam.; bracts 3–4, horizontal to slightly reflexed, flat, 1–6 cm × 1–2 mm. Spikelets 50–70(–100), stipitate, ovate, 2.5–4 × 2–3 mm; floral scales dull greenish white to stramineous, midvein with laciniate keel ± as long as scale, 1 mm wide, laterally 2-veined, ovate, 2.2–3.8 × 2 mm, acuminate; stamens (1–)2; anthers 2 mm; style 1 mm; stigmas 1.5–2 mm. Achenes chestnut brown to purplish brown, ovoid, 1.5–2 × 1.2 mm, base sessile, apex apiculate, puncticulate.

Fruiting summer. Lawns, farmlands; 0–50 m; introduced; Fla.; West Indies; native tropical Asia.