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American bulrush, chair-maker's club-bulrush, chairmaker's bulrush, Olney bulrush, Olney's bulrush, Olney's three-square bulrush, schoenoplectus

Rhizomes

2–5 mm diam.

Culms

sharply trigonous, sides deeply concave throughout to rarely nearly flat, 0.4–2.5 m × 3–10 mm.

Leaves

ca. 3, basal, less than 1/2 culm length;

sheath fronts not pinnate-fibrillose;

blades 1–3, V-shaped near base, otherwise laterally flattened-trigonous in cross section;

distal blade 0.2–1.5 times as long as sheath, 25–200 × 2–8 mm.

Inflorescences

capitate or very rarely with 1 branch to 5 mm;

proximal bract usually erect, resembling leaf blade, 1–6 cm.

Spikelets

2–20, 5–15 × 3–5 mm;

scales bright orange- to red- or purple-brown to straw-colored, often partly translucent, usually clearly lineolate-spotted, broadly ovate, 2.7–4 × 2–3 mm, smooth or awn sparsely spinulose, margins deciduously ciliolate, flanks of proximal scale often with several ribs, apex rounded to acute, notch 0.1–0.4 mm deep, awn not contorted, 0.2–0.6 mm.

Flowers

perianth members (2–)5–6(–7), yellow-brown, bristlelike, slender to stout, often unequal to equaling 1/2 achene body, retrorsely spinulose;

anthers 1.5–3 mm;

styles 2-fid or 2-fid and 3-fid.

Achenes

brown when ripe, thickly plano-convex or unequally biconvex or compressed obtusely trigonous, obovoid, 1.8–2.8 × 1.3–2 mm;

beak 0.1–0.3 mm.

2n

= 78.

Schoenoplectus americanus

Phenology Fruiting spring–summer (south), summer (north).
Habitat Brackish or mineral-rich shores, marshes, fens
Elevation 0–2200 m (0–7200 ft)
Distribution
from FNA
AL; AZ; CA; CT; DE; FL; GA; ID; KS; LA; MA; MD; ME; MI; MO; MS; NC; NH; NJ; NM; NV; NY; OK; OR; RI; SC; TX; UT; VA; VT; WA; WY; BC; NS; Mexico; Central America; South America; West Indies (Puerto Rico)
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Discussion

The secondary involucral bracts of Schoenoplectus americanus lack blades and closely resemble floral scales, in contrast to S. pungens and S. deltarum. Although mostly very locally distributed, S. americanus is ecologically important in many coastal marshes. In recent years it has seriously declined (e.g., in Maryland and Louisiana). It may occur in southwestern Kansas; I have not seen a specimen. It probably has been extirpated from the Missouri station, based on one collection from 1886 (G. Yatskievych, pers. comm.). The report from New Hampshire is based on M. L. Fernald (1950). The stations on the Maine and Connecticut coasts, at Lake Champlain in Vermont, and in Oklahoma are based on putative S. americanus × S. pungens specimens. Some plants in the southwest are atypical in having nearly flat culm sides and leaf blades to 1.5 times as long as their sheaths as in the type of Scirpus monophyllus J. Presl & C. Presl from Peru. The name Scirpes americanus was long misapplied to Schoenoplectus pungens; Schoenoplectus americanus was known as Scirpus olneyi (A. E. Schuyler 1974).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 23, p. 52.
Parent taxa Cyperaceae > Schoenoplectus > sect. Schoenoplectus
Sibling taxa
S. acutus, S. californicus, S. deltarum, S. erectus, S. etuberculatus, S. hallii, S. heterochaetus, S. mucronatus, S. pungens, S. purshianus, S. saximontanus, S. smithii, S. subterminalis, S. tabernaemontani, S. torreyi, S. triqueter
Synonyms Scirpus americanus, Scirpus olneyi
Name authority (Persoon) Volkart ex Schinz & R. Keller: Fl. Schweiz ed. 2, 1: 75. (1905)
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