Schoenoplectus heterochaetus

(Chase) Soják

Cas. Nár. Mus., Odd. Prír. 140: 127. 1972.

Common names: Slender bulrush scirpe à sois inégales
IllustratedEndemic
Basionym: Scirpus heterochaetus Chase Rhodora 6: 70, plate 53, fig. d. 1904
Synonyms: Scirpus lacustris var. tenuiculmis E. Sheldon
Treatment appears in FNA Volume 23. Treatment on page 49. Mentioned on page 45, 47, 48, 50.

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 orangebrown to nearly colorless, usually obscurely lineolate-spotted, midribs often greenish, ovateoblong, 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 graybrown, compressedtrigonous, obovoid, 2.2–3.2 × 1.4–1.9 mm; beak 0.3–1 mm. 2n = 38.


Phenology: Fruiting summer.
Habitat: Fresh, often calcareous marshes and lakes, often emergent in water to 1.5 m
Elevation: 10–500(–2000) m

Distribution

V23 68-distribution-map.jpg

Alta., Man., Ont., Que., Calif., Idaho, Ill., Iowa, Kans., Mass., Mich., Minn., Mo., Mont., Nebr., N.Y., N.Dak., Okla., Oreg., Pa., S.Dak., Vt., Wis., Wyo.

Discussion

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.

Selected References

None.

Lower Taxa

None.
abaxial +  and adaxial +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.32 cm3.2 mm <br />0.0032 m <br />) +
with transverse wavy ridges +  and rugose +
1.4mm;1.9mm +
2 cm20 mm <br />0.02 m <br /> (?) +
S. Galen Smith +
(Chase) Soják +
straight +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
shortened +
deciduous +
enlarged +
Scirpus heterochaetus +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
rudimentary +
1 (?) +  and 2 (?) +
c--shaped +
shorter to longer +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
parallel +  and divergent +
terete +, rolled +  and plicate +
Slender bulrush +  and scirpe à sois inégales +
dorsiventrally flat +  and c-shaped or laterally compressed +
2mm +  and 10mm +
150 cm1,500 mm <br />1.5 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +
cylindric +
4mm;8mm +
0 cm0 mm <br />0 m <br /> (22 cm220 mm <br />0.22 m <br />) +
0 cm0 mm <br />0 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Alta. +, Man. +, Ont. +, Que. +, Calif. +, Idaho +, Ill. +, Iowa +, Kans. +, Mass. +, Mich. +, Minn. +, Mo. +, Mont. +, Nebr. +, N.Y. +, N.Dak. +, Okla. +, Oreg. +, Pa. +, S.Dak. +, Vt. +, Wis. +  and Wyo. +
10–500(–2000) m +
hypogynous +  and subtending +
membranous-translucent +
pinnate-fibrillose +
biconvex +  and trigonous +
Fresh, often calcareous marshes and lakes, often emergent in water to 1.5 m +
concavo-convex +
1-3 times branched or capitate or of 1 spikelet +
0 cm0 mm <br />0 m <br /> (9 cm90 mm <br />0.09 m <br />) +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
1 cm10 mm <br />0.01 m <br /> (?) +
membranous +
scabridulous +
reddish +  and greenish +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
straw-colored-scabrous +
v--shaped +
curved +  and straight +
with (1-)3-6(-30) bristles and/or scales +
Fruiting summer. +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
thickly c-shaped;subterete +
1 cm10 mm <br />0.01 m <br /> (15 cm150 mm <br />0.15 m <br />) +
Cas. Nár. Mus., Odd. Prír. +
0.5 cm5 mm <br />0.005 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
adventitious +
lineolate-spotted +, light orangebrown +  and nearly colorless +
disintegrating +
deciduous +
basal +  and proximal +
2-keeled +
Illustrated +  and Endemic +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
2 +, 5 +  and 30 +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
Scirpus lacustris var. tenuiculmis +
Schoenoplectus heterochaetus +
Schoenoplectus sect. Schoenoplectus +
species +
not +  and rhizomatous +