Schoenoplectus pungens
Schoenoplectus hallii
American bulrush, chair-maker's rush, chairmaker's clubrush, common three-square, common three-square bulrush, schoenoplectus, scirpe acere, three-square club-bulrush, western bulrush
Hall's annual-bulrush, Hall's bulrush
often vertical, 1–6 mm diam., firm to hard;
scales shorter to longer than internodes, disintegrating to fibers.
sharply trigonous, sides convex to concave proximally, deeply concave to flat distally, 0.1–2 m × 1–6 mm, smooth.
often arching to decumbent, cylindric, ridged when dry, 0.05–0.8 m × 0.5–1 mm.
basal;
sheath fronts membranous distally, orifice adaxially truncate to concave, often splitting;
ligules 2-fid, 1 mm;
blades 2–6, proximally V-shaped, distally trigonous to asymmetrically laterally flattened in cross section, angles often scabridulous distally;
distal blade (1–)2–5 times as long as sheath, 50–750 × 2–9 mm.
3–4, 1 cauline;
sheaths straw-colored to brown and disintegrating to fibers, front translucent and splitting;
blades 1–2, proximally thickly C-shaped in cross section, distally flat, from much shorter to longer than sheath, 1–200+ × 0.2–1 mm, smooth or margins distally spinulose.
capitate;
proximal bract usually erect, resembling leaf blade but trigonous proximally, (1–)3–20 cm.
capitate or 1 spikelet or rarely with 1 or 2 branches to 12 mm;
proximal bract erect, resembling leaf blades, 5–150 mm.
1–5(–10), 5–23 × 3–5(–7) mm;
scales bright (to very dark) orange-, red-brown, or purplish brown to straw-colored, often prominently lineolate-spotted, midrib mostly paler, ovate, 3.5–6 × 2–3 mm, smooth or awn sparsely spinulose, margins deciduously ciliolate, flanks ribless except sometimes proximal scales, midrib prominent, apex acute (to obtuse), 2-fid, notch (0.3–)0.5–1 mm deep, awn mostly irregularly bent, 0.5–1.5(–2.5) mm.
achenes blackish brown, plano-convex or usually the adaxial surface longitudinally concave, ovoid to obovoid, 1.3–1.7 × 1.2–1.3 mm, with 15–18 mostly sharp ridges;
beak 0.1 mm.
perianth members 4–8, sometimes fewer, brown, bristlelike, variably slender to stout, equal or unequal, all equaling achene body to all rudimentary, retrorsely spinulose;
anthers 2–3 mm;
styles 2–3-fid.
perianth absent;
anthers 0.4 mm;
styles 2-fid.
brown, biconvex to compressed bluntly trigonous, obovoid to obpyriform, (2–)2.5–3.5 × 1.3–2.3 mm;
beak 0.1–0.5 mm.
achenes thickly trigonous with convex abaxial face, 1.7–2.5 × 1.1–1.6 mm, rugose with rounded ridges;
beak 0.3 mm.
= 74, 78.
= 22.
Schoenoplectus pungens
Schoenoplectus hallii
Three varieties of Schoenoplectus pungens (under Scirpus americanus) were recognized for North America by T. Koyama (1963), and three more or less equivalent varieties were recognized by S. G. Smith (1995). These varieties are described informally and illustrated here but not formally recognized because their morphologic delimitation should be evaluated and their exact ranges are still uncertain.
Schoenoplectus pungens (Vahl) Palla var. pungens has brown to straw-colored spikelet scales, bifid styles, and lenticular achenes. It is the only variety that occurs in Europe and North America. In North America, it extends from the Atlantic Coast to Saskatoon and is reported from Arkansas, Kansas, Louisiana, Minnesota, and Missouri.
Schoenoplectus pungens (Vahl) Palla var. longispicatus (Britton) S. G. Smith has bright orange to reddish (or purplish) brown or often stramineus and lineolate-spotted spikelet scales, trifid styles, and trigonous to lenticular achenes. Endemic to the flora area, variety longispicatus occurs in western North America, except Pacific Coast, east to Saskatoon, Manitoba, and Ontario, along the north shore of Lake Superior, south to Iowa, Minnesota, western Wisconsin, Missouri, and southern Mississippi.
Schoenoplectus pungens (Vahl) Palla var. badius (J. Presl & C. Presl) S. G. Smith has uniformly dark chestnut spikelet scales, trifid styles 3-fid, and trigonous or thickly biconvex achenes. In North America, variety badius occurs along the Pacific Coast (to slightly inland) from British Columbia south to California. Outside the flora area it occurs in Baja California, Mexico, temperate South America, Australia, including Tasmania, and New Zealand.
The name Scirpus americanus [subsp. monophyllus (J. Presl & C. Presl) T. Koyama] var. monophyllus was misapplied to Schoenoplectus pungens var. badius (T. Koyama 1963). The type of the basionym Scirpus monophyllus J. Presl & C. Presl from Peru belongs to Schoenoplectus americanus (S. G. Smith 1995).
Schoenoplectus americanus, S. pungens, and S. deltarum belong to the small “Scirpus americanus complex” T. Koyama (1963), in which the species are sometimes difficult to delimit. Schoenoplectus pungens was long known incorrectly as S. americanus Persoon; the type of that name is conspecific with plants formerly treated as S. olneyi A. Gray (A. E. Schuyler 1974). Putative Schoenoplectus pungens × S. americanus hybrids [= S. ×contortus (Eames) S. G. Smith] are locally common. 2n = ca. 86–128.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Many reports of Schoenoplectus hallii are based on misidentified specimens of S. saximontanus or S. erectus. The Iowa specimen was probably collected in 1890. The species is probably extirpated from Massachusetts. I have identified a specimen from the Georgia coastal plain, where S. hallii and S. erectus are sympatric, as intermediate between the two.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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