Tidalmarsh flatsedge

Chlorocyperus serotinus (Rottbøll) Palla; Juncellus serotinus (Rottbøll) C. B. Clarke

Herbs, perennial, stoloniferous; stolons terminated by tubers. Culms trigonous, 50–100 cm × 5–8 mm, glabrous. Leaves 3–6, V-shaped, 20–50 cm × 5–8(–10) mm. Inflorescences: spikes not appearing lateral, rays 5–8, 2–7(–12) cm; bracts 3–4, ± horizontal to ascending at 45°, V-shaped, 5–25 cm × 1.5–8 mm; spikes 1–4, ovoid, 2–4 × 2–3 cm; rachis 1–2.7 cm, smooth or hispidulous; rachilla persistent, wingless or with hyaline wings scarcely 0.1 mm wide. Spikelets 7–14, flattened, lanceoloid, 10–20 × 2–2.5 mm; floral scales 10–30, laterally dark brown to reddish brown, medially greenish, laterally 5–9-ribbed, ovate-deltate; anthers 3, 0.5 mm; styles 0.5 mm; stigmas 1.2–1.6 mm. Achenes brown, sessile, ellipsoid, 1.4–1.6 × 1.4–1.5 mm, apex obtuse, apiculate.

Fruiting summer. Tidal marshes; 0 m; introduced; Del., N.J., Pa.; Eurasia.