Schoenoplectus americanus

(Persoon) Volkart ex Schinz & R. Keller

Fl. Schweiz ed. 2, 1: 75. 1905.

Common names: Olney’s three-square bulrush
Illustrated
Basionym: Scirpus americanus Persoon Syn. Pl. 1: 68. 1805
Synonyms: Scirpus olneyi A. Gray
Treatment appears in FNA Volume 23. Treatment on page 52. Mentioned on page 46, 51, 53.

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), yellowbrown, 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 planoconvex or unequally biconvex or compressed obtusely trigonous, obovoid, 1.8–2.8 × 1.3–2 mm; beak 0.1–0.3 mm. 2n = 78.


Phenology: Fruiting spring–summer (south), summer (north).
Habitat: Brackish or mineral-rich shores, marshes, fens
Elevation: 0–2200 m

Distribution

V23 73-distribution-map.jpg

B.C., N.S., Ala., Ariz., Calif., Conn., Del., Fla., Ga., Idaho, Kans., La., Maine, Md., Mass., Mich., Miss., Mo., Nev., N.H., N.J., N.Mex., N.Y., N.C., Okla., Oreg., R.I., S.C., Tex., Utah, Vt., Va., Wash., Wyo., Mexico, West Indies (Puerto Rico), Central America, South America

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).

Selected References

None.

Lower Taxa

None.

"prolonged" is not a number.

... more about "Schoenoplectus americanus"
0.18 cm1.8 mm <br />0.0018 m <br /> (0.28 cm2.8 mm <br />0.0028 m <br />) +
with transverse wavy ridges +  and rugose +
obovoid;trigonous;compressed;biconvex;planoconvex +
1.3mm;2mm +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
S. Galen Smith +
(Persoon) Volkart ex Schinz & R. Keller +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
shortened +
0 +  and 1/2 +
deciduous +
enlarged +
Scirpus americanus +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
rudimentary +
1 (?) +  and 3 (?) +
flattened-trigonous +  and v--shaped +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
parallel +  and divergent +
terete +, rolled +  and plicate +
Olney’s three-square bulrush +
dorsiventrally flat +  and c-shaped or laterally compressed +
2mm +  and 10mm +
trigonous +
2.5 cm25 mm <br />0.025 m <br /> (20 cm200 mm <br />0.2 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
B.C. +, N.S. +, Ala. +, Ariz. +, Calif. +, Conn. +, Del. +, Fla. +, Ga. +, Idaho +, Kans. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Miss. +, Mo. +, Nev. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, Okla. +, Oreg. +, R.I. +, S.C. +, Tex. +, Utah +, Vt. +, Va. +, Wash. +, Wyo. +, Mexico +, West Indies (Puerto Rico) +, Central America +  and South America +
0–2200 m +
hypogynous +  and subtending +
biconvex +  and trigonous +
Brackish or mineral-rich shores, marshes, fens +
very rarely +  and capitate +
1-3 times branched or capitate or of 1 spikelet +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
cauline +  and basal +
membranous +
curved +  and straight +
1/2 +, 5 +  and 6 +
with (1-)3-6(-30) bristles and/or scales +
Fruiting spring–summer (south), summer (north). +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
1 cm10 mm <br />0.01 m <br /> (6 cm60 mm <br />0.06 m <br />) +
Fl. Schweiz ed. +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
adventitious +
lineolate-spotted +, bright orange +  and red or purple-brown +
deciduous +
0.27 cm2.7 mm <br />0.0027 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
basal +  and proximal +
2mm;3mm +
not pinnate-fibrillose +
40 cm400 mm <br />0.4 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +
concave +
0.3 cm3 mm <br />0.003 m <br /> (?) +  and 1 cm10 mm <br />0.01 m <br /> (?) +
W2 +, W1 +  and Illustrated +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
2 +  and 20 +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
3-fid +  and 2-fid +
Scirpus olneyi +
Schoenoplectus americanus +
Schoenoplectus sect. Schoenoplectus +
species +
not +  and rhizomatous +