17. Scirpus pedicellatus Fernald, Rhodora. 2: 16. 1900.
Scirpus cyperinus (Linnaeus) Kunth var. pedicellatus (Fernald) Schuyler
Plants aggregated in dense tussocks; rhizomes branching, short, tough, fibrous. Culms: fertile ones upright or nearly so; nodes without axillary bulblets. Leaves ca. 8 per culm; sheaths of proximal leaves green or brownish; proximal sheaths and blades with septa few to many, consipuous or inconspicuous; blades 42–77 cm × 5–9 mm. Inflorescences terminal; rays ascending, scabrous throughout or main branches smooth proximally, rays rarely with axillary bulblets; bases of involucral bracts green, brown, or blackish, not glutinous. Spikelets in open cymes, central spikelet of each cyme sessile, others usually pedicellate, spikelets ovoid, 3–9 × 2–3 mm; scales usually pale brown, black pigment absent (or sometimes a little beside distal midrib), oblong-elliptic, 1.4–1.8 mm, rounded or weakly mucronate, mucro (if present) to 0.1 mm. Flowers: perianth bristles persistent, 6, slender, contorted, much longer than achene, smooth, projecting beyond scales, mature inflorescence appearing woolly; styles 3-fid. Achenes whitish, elliptic or obovate in outline, plumply trigonous or plano-convex, 0.7–0.9 ´ 0.4–0.5 mm. 2n = 68.
Fruiting summer (mid or late Jul). Usually in lowland marshes in stream valleys, edges of bogs, boggy meadows, and wet sandy shorelines; 0–500 m; N.B., N.S., Ont., Que.; Conn., Ill., Ind., Iowa, Maine, Mass., Mich., Minn., Mo., N.H., N.J., N.Y., Ohio, Pa., R.I., Vt., Wis.
Scirpus pedicellatus often hybridizes with S. cyperinus and forms hybrid swarms.