Schoenoplectus etuberculatus (Steud.) Soják

Scirpus etuberculatus was placed in Scirpus sect. Bolboschoenus by T. Koyama (1958) and G. C. Tucker (1987).

Plants mat-forming; rhizomes 1–3 mm diam. Culms proximally bluntly and distally sharply trigonous, 0.6–2 m × 3–5 mm. Leaves 5–20+, nearly equaling culm; sheath fronts delicately pinnate-fibrillose; blades 2–6+, smooth; distal blade longer than sheath, 2–10 mm wide, smooth; emergent blades stiff, cross section thickly V-shaped to trigonous near ligule, central region acutely trigonous and laterally flattened, distal region laterally flattened, apex often asymmetric; submerged blades often flaccid, ribbonlike. Inflorescences 2–3 times branched, 2–3 proximal internodes elongated, branches to 16 cm; proximal bract erect, resembling emergent leaf blade, 7–32 cm. Spikelets 3–20, 10–25 × 5–6 mm; scales straw-colored to orange-brown or flanks red, central region usually greenish, aging brown, ovate-lanceolate, 5–7 × 3 mm, smooth, margins sometimes ciliolate at 40X, apex acute, entire, mucro to 0.2 mm. Flowers: perianth bristles 6, medium brown to reddish, equaling achene, sparsely spinulose; anthers 3–3.5 mm; styles 3-fid. Achenes medium brown, ovoid to obovoid, compressed-trigonous, 3–4.5 × 1.7–2 mm; beak 0.7–2 mm.

Ala., Del., Fla., Ga., La., Md., Miss., Mo., N.C., R.I., S.C., Tex., Va.

Fruiting late spring–summer.

Emergent (to submerged), in fresh to slightly brackish ponds and marshes, spring-fed streams, mainly on coastal plains; 10–100m.

Rhynchospora etuberculata Steudel, Syn. Pl. Glumac. 2: 142. 1855; Scirpus etuberculatus (Steudel) Kuntze

Scirpus etuberculatus (Steud.) Kuntze, Rev. Gen. 2: 758. 1891.
Scirpus tnaritimus y cylindricus Torr. Ann. Lye. N. Y. 3: 325. 1836.
Rhynchospora etuberculata Steud. Syn. PI. Cyp. 142. 1855.
Scirpus tnacranthus Bock. Flora 41: 412. 1858.
Scirpus leptolepis Chapm. Fl. S. U. S. 520. 1860.
Scirpus Canbyi A. Gray; Canby, Proc. Acad. Phila. 1864: 18. 1864.
Scirpus cylindricus Britton, Trans. N. Y. Acad. 11: 79. 1892.
Perennial; culms 1-1.5 m. tall, 5-10 mm. broad at the base, very soft and spongy, smooth, obscurely trigonous, erect from a scaly, reddish rhizome ca. 3 mm. thick; blades 1-several,
* The principal divisions of the genus in Reichenbach's treatment are here interpreted as of sectional rank. elongate, arising at the base and nearly equaling the culm, smooth, flat, soft, blunt-tipped, ca. 6-8 mm. broad near the base, narrowing upwards; outer involucral bract 2-3 dm. long, smooth, blunt-tipped, obscurely trigonous; second involucral bract often present, to 1 dm. long; spikelets ca. 2 mm. long, 6-20 on smooth rays to 1 dm. long; scales ca. 6 mm. long, narrow, glabrous, blunt-tipped, brown or slightly reddish; style trifid; bristles 6, somewhat scabrous above, equaling the tubercle; body of the achene 3.5-4 mm. long, dark-brown, smooth, trigonous, the prominent tubercle 1 mm. long.
Type locality: Louisiana.
Distribution: Swamps near the coast; Maryland, south to Florida, west to Louisiana.

Schoenoplectus etuberculatus, common name Canby's bulrush, is a plant species native to the United States. It is reported from every state on the Gulf and Atlantic coasts from eastern Texas to Delaware, plus isolated populations in Rhode Island (one population in Town of South Kingstown, Washington County) and Missouri (Oregon County). It is an emergent plant growing in ponds, marshes, stream banks, etc., including in brackish water along the coast.

Schoenoplectus etuberculatus is a mat-forming perennial herb spreading by means of underground rhizomes. Culms are up to 2 m (80 inches) tall, triangular in cross-section. Leaves are up to 20 cm (8 inches) long. Inflorescence is branched 2 or 3 times, bearing spikelets that are red, orange or straw-colored. Achenes are egg-shaped, about 4 mm (about 0.16 inches)across.

Schoenoplectus etuberculatus là loài thực vật có hoa trong họ Cói. Loài này được (Steud.) Soják miêu tả khoa học đầu tiên năm 1972.