Description

Key Characters:

Growth Form: Robust perennials, with horizontal, long–creeping rhizomes, also bearing tubers.

Stems: Rhizomes repent, clothed with brown scales, forming ligneous tubers at culm bases and nodes, culms erect, with several nodes, leafy, trigonous, smooth, 30–150 cm tall.

Roots:

Leaves: Leaves simple. Alternate. Blades linear, 3–8 mm wide. Apex acuminate. Surfaces scabrous on distal margins and midrib toward apex on lower surface, otherwise smooth. Margins entire. Sheathing; basal sheaths brown. Stipules absent.

Flowers: Flowers in inflorescences moderately dense, anthelate, consisting of terminal, congested, head-like clusters of 3 to numerous spikelets, +/- with 1–4 rays, each terminated by a headlike cluster of spikelets, the rays up to 5 cm long; involucral bracts 2–5, the lower ones much surpassing the inflorescence, the longest up to 30 cm long; spikelets pale brown, ellipsoid, ovoid–ellipsoid, or subcylindrical, terete (cylindrical), 1–2.5 cm long, 0.6–1 cm in diameter, apex rounded and abruptly contracted in subsp. paludosus and more gradually acute and attenuate in subsp. maritimus; glumes pale brown with pale margins, thin, membranous, narrowly ovate, 5–6.5 mm long, ca. 3 mm wide, tapering to an acute, bifid apex, pubescent externally, 1(3)– nerved, the midnerve prolonged ca. 2 mm beyond the apex. Flowers bisexual (perfect). Perianth bristles 2–6, up to ca. ½ as long as the achene, caducous. Corolla (petals) absent. Stamens 3. Ovary superior.

Fruit: Achenes brown; glossy; obovate; 3–4 mm long; 1.8–2.2 mm wide; lenticular; puncticulate; apex apiculate. Seeds 1; seed coat thin; free from pericarp; embryo basal; endosperm abundant.

Ploidy: 2n = 40; 76–77; 80; 86; 90; 96; 104; 106; 110; 114

Habitat: Primarily in coastal sites.

Elevation Range: 0–6 m.