Schoenoplectus heterochaetus (Chase) Soják

Schoenoplectus heterochaetus hybridizes with S. acutus and S. tabernaemontani (see comment under 1. S. tabernaemontani).

The Michigan record is dubious, the Oregon record is from 1895, and reports from Washington are apparently based on misidentified specimens. Some specimens from scattered localities in Eurasia may be Schoenoplectus heterochaetus.

Schoenoplectus lacustris (Linnaeus) Palla, of Eurasia, was collected near Camden, New Jersey, in 1889 and 1891; it now appears to be extirpated. It is also in cultivation in North America and should be sought. It is similar to S. heterochaetus, from which it differs in its often clustered spikelets, six long perianth bristles, and ability to form submerged ribbon-leaved forms, especially in flowing water in streams. 2n = 42.

Schoenoplectus lacustris hybridizes in Europe with S. tabernaemontani and S. triqueter.

Rhizomes 5–8 mm diam.; scales longer than internodes, disintegrating to fibers. Culms cylindric, 1.5–2.5 m × 4–8 mm. Leaves basal; sheaths often separating from culm, resembling blade, sometimes reddish proximally, front membranous-translucent, splitting, and delicately pinnate-fibrillose, orifice adaxially deeply V-shaped; ligules entire, 1 mm; blades 1–2, thinly C-shaped to thin and dorsiventrally flat in cross section, much shorter to longer than sheath, distal blade to 220 × 5 mm. Inflorescences 2× branched, open, plano- to concavo-convex, to 9 cm; proximal bract usually erect, thickly C-shaped to subterete in cross section, 1–15 cm, margins often scabridulous. Spikelets 5–30, solitary or rarely 2 together, 5–15 × 3–4 mm; scales light orange-brown to nearly colorless, usually obscurely lineolate-spotted, midribs often greenish, ovate-oblong, 3–4 × 1.5 mm, sparsely reddish- or straw-colored-scabrous distally on awn, sometimes midrib, and rarely adjacent parts of sides, margins ciliate, hairs contorted, flanks veinless, apex obtuse, notch 0.5 mm deep, awn straight to slightly contorted, 0.3–1 mm. Flowers: perianth members 4(–5), brown, bristlelike, equaling achene body or adaxial and abaxial much shorter, sparsely retrorsely spinulose; anthers 2 mm; styles 3-fid. Achenes dark gray-brown, compressed-trigonous, obovoid, 2.2–3.2 × 1.4–1.9 mm; beak 0.3–1 mm. 2n = 38.

10–500(–2000)

Fruiting summer.

Fresh, often calcareous marshes and lakes, often emergent in water to 1.5m.

Scirpus heterochaetus Chase, Rhodora 6: 70, plate 53, fig. d. 1904; S. lacustris Linnaeus var. tenuiculmis E. Sheldon

Scirpus heterochaetus Chase, Rhodora 6: 70. 1904
Scirpus lacustris var. tenuiculmis Sheldon, Minn. Bot. Stud. 2: 583. 1896.
Roots fibrous, red or purplish; culms 1-2 m. tall, 1-2 mm. broad at the summit, 1-1.5 cm. broad at the base, erect from rhizomes covered with purplish scales, green, terete, very slender, strong, smooth, sheathed at the base by 2-3 rudimentary leaves, these abruptly contracted to the mucronate blade, to 2 dm. long, smooth; inflorescence paniculate, the spikelets single on very slender, smooth or scabrous-margined rays, the primary to 8 cm. long, the secondary to 3 cm., no tertiary observed; outer involucral bract 3-7 cm. long, smooth, erect; bractlets 4—5 mm. long, pale brown flecked with darker brown, smooth with a scabrous-margined, mucronate tip, the margins entire becoming lacerate; spikelets 0.75-1.5 cm. long, 3-5 mm. broad, ovoid to cylindric, usually not more than 25, brown, many-flowered; scales 4 mm. long, 2 mm. broad, pale brown flecked with darker brown, ovate-oblong, bifurcate, the tip scabrous, mucronate; bristles 2-4, irregular, occasionally nearly equaling the achene, retrorsely barbed, reddishbrown; style bifid or more commonly trifid; body of the mature achene 2.5 mm. long, 2.25-3 mm. broad, dark brown, trigonous, reticulate, the mucronate tip nearly 1 mm. long.
* The primary divisions of the genus in Endlicher's treatment are here interpreted as of sectional rank. Type locality: Havana, New York.
Distribution: Freshwater lakes and streams; southeastern Canada and northeastern United States; central United States; of rare occurrence in the northwestern United States.

Schoenoplectus heterochaetus is a species of flowering plant in the sedge family known by the common name slender bulrush. It is native to North America, where it can be found in scattered locations in Canada and the United States.

Schoenoplectus heterochaetus grows in a variety of wetland habitat types, including marshes and lakes. It grows on land or in shallow water. It is a perennial herb growing from a large rhizome system. Its cylindrical stems grow erect to maximum heights sometimes exceeding two meters. The leaves are mostly located at the base of the stem, sheathing around it. The inflorescence is a panicle of many cone-shaped spikelets on long, thin branches.

Schoenoplectus heterochaetus là loài thực vật có hoa trong họ Cói. Loài này được (Chase) Soják miêu tả khoa học đầu tiên năm 1927.