Description

Key Characters:

Growth Form: Annuals or short-lived perennials, rarely with short rhizomes.

Stems: culms pale green, dull, densely tufted, subterete or obtusely several­ angled, 15–70 cm tall, 1–4 mm in diameter below.

Roots: Fibrous root system.

Leaves: Leaves simple. Alternate Leaves reduced to 3–4 bladeless sheaths. Margins entire. Sheathing; lower sheaths brown, scale-like, upper sheaths pale green, up to 15 cm long. Stipules absent.

Flowers: Flowers in inflorescences anthelate, head-like with 2– 10 spikelets; involucral bracts erect, 5–15 cm long, with a furrow on upper surface toward base; spikelets pale yellowish brown, sessile, oblong to ovoid–oblong, 6– 18 mm long, 3–6 mm wide, acute; glumes pale brown, membranous, ovate to elliptic­ ovate, 3–4 mm long, 1.8–2.5 mm wide, weakly 3–nerved, the nerves green, apex subentire, mucronate; bristles 4–6, 4 of them as long as or slightly surpassing the achene, the remainder ½ as long as the achene or shorter; stigmas 2, rarely retain­ing the vestige of the third stigma. Flowers bisexual (perfect). Corolla (petals) absent. Stamens 3. Ovary superior.

Fruit: Nutlets dark brown at maturity; broadly obovate; ca. 2 mm; plano-convex; obscurely transversely wrinkled; shiny. Achenes dark brown; broadly obovate; lenticular; 1.8–2 mm long; ca. 1.5 mm wide; transversely wrinkled; apex mucronate. Seeds 1; seed coat thin; free from pericarp; embryo basal; endosperm abundant.

Ploidy: 2n = 70*; 76

Habitat: Occurring in and around bogs; pond margins; and in wet forest.

Elevation Range: (5–)180–1,370 m.