Schoenoplectus pungens
Schoenoplectus acutus
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
common tule, hard-stem bulrush, hard-stem club-bulrush, schoenoplectus, viscous bulrush
often vertical, 1–6 mm diam., firm to hard;
scales shorter to longer than internodes, disintegrating to fibers.
5–15 mm diam.
sharply trigonous, sides convex to concave proximally, deeply concave to flat distally, 0.1–2 m × 1–6 mm, smooth.
cylindric, 1–4 m × 2–10 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, all basal;
sheaths often dark reddish proximally, front membranous-translucent and splitting, orifice adaxially deeply V-shaped;
blades 1–2, C-shaped to dorsiventrally flat in cross section, usually much shorter than sheath, distal blade 8–120 × 3–7 mm, margins often scabridulous.
capitate;
proximal bract usually erect, resembling leaf blade but trigonous proximally, (1–)3–20 cm.
2(–3) times branched, open or compact, branches 6(–18) cm;
proximal bract usually erect, thickly C-shaped in cross section, 1–9 cm, margins sometimes scabridulous.
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.
3–190, solitary or in clusters of 2–8, never all solitary;
scales reddish to orange-brown to straw-colored, often variable on same scale, usually wholly or partly straw-colored and prominently lineolate-spotted at 10X, scale or midrib often green when young, ovate, 3–4 × 2–3 mm, sparsely to often densely reddish or straw-colored spinulose-papillose distally or on most of surface, margins ciliate, hairs long, contorted, flanks veinless, apex acute to obtuse, notch 0.3–0.5 mm deep, awn on at least some scales in spikelet usually strongly contorted, 0.5–2 mm (often broken off).
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 members (4–)6(–8), brown, bristlelike, equaling achene body or sometimes much shorter, rarely rudimentary, spinulose;
anthers 2 mm;
styles 2(–3)-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.
dark gray-brown, plano-convex or rarely weakly trigonous, obovoid, (1.5–)2–3 1.2–1.7 mm;
beak 0.2–0.4 mm.
= 74, 78.
Schoenoplectus pungens
Schoenoplectus acutus
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.)
Varieties 2 (2 in the flora).
Plants of Schoenoplectus acutus var. occidentalis that have most styles 3-fid, most achenes trigonous, and culms very soft with large air cavities occur at lower elevations in California (mostly southern) and Baja California. In California they often grow on stream bars. They may deserve varietal status. The varieties intergrade throughout most of the west with var. occidentalis.
Schoenoplectus acutus hybridizes with Schoenoplectus tabernaemontani, S. heterochaetus, and S. californicus (see also S. tabernaemontani).
Although previously assumed to be restricted to North America, some specimens from Eurasia are probably Schoenoplectus acutus, and one very young specimen from Clipperton Island in the eastern Pacific is probably S. acutus var. occidentalis.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Styles 2-fid; achenes plano-convex; culms mostly very firm, air cavities in distal 1/4 mostly ca. 0.5 mm wide. | var. acutus |
1. Some styles 3-fid; some achenes compressed, obtusely trigonous; culms firm to soft, larger air cavities in distal 1/4 1–2.5 mm wide. | var. occidentalis |
- Local floras:
BC, 
OR, 
WA - Local Web sites:
CalFlora, CalPhotos, 
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
LA Plants, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
- Local floras: BC, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW, Go Botany, IL Wildflowers, KS Wildflowers, MD Biodiversity, MI Flora, MN Wildflowers, MO Plants, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
