Foothill Flat Sedge

Herbs, annual, cespitose. Culms 1–10(–25), roundly trigonous, 3–12 cm × 0.3–0.8 mm, glabrous. Leaves 1–3–(4), 1–6 cm × 1(–1.5) mm. Inflorescences: if rays absent heads single, dense, sessile, digitate, 5–20 × 10–30 mm, single heads 10–30(–50) mm; rays usually absent, if present 1–8 cm; 2d order rays infrequently present, 1–2 cm; bracts 3–6, erect to oblique, flat to V-shaped,(0.5–)2–10(–15) cm × 0.5–2 mm. Spikelets 5–10(–20), linear to linear-lanceoloid, (5–)8–12(–35) × 1.6–2.3(–2.5) mm; floral scales (6–)16–30(–76), laterally glossy reddish brown to brown, medially greenish, sometimes also reddish or brownish, laterally ribless, medially strongly 3-ribbed, ovate-lanceolate, 1.9–2(–2.3) mm (including prominent excurved cusp of 0.3–0.5 mm) × 0.8–1.1 mm, apex truncate, emarginate, or cuspidate. Flowers: stamens (1–)2–3; anthers ellipsoid, 0.3 mm, connectives not prolonged; styles 0.3–0.4 mm; stigmas 0.4–0.7 mm. Achenes brown, slightly stipitate, obovoid to oblong, 0.8–0.9 × 0.4–0.5 mm, apex abruptly apiculate, surfaces papillose.

Ariz.; Mexico; Central America; South America; Asia; Africa.

Fruiting summer.

Seasonally wet, sandy soils; 500m.

Cyperus amabilis var. macrostachyus (Boeckeler) Kükenthal; C. aurantiacus Kunth; C. aureus Kunth; C. aureus var. aurantiacus (Kunth) Boeckeler; C. aureus var. macrostachyus Boeckeler; C. aureus var. oligostachyus (Kunth) Boeckeler; C. microstachyus Vahl; C. oligostachyus Kunth