Cyperus flavescens

Linnaeus

Sp. Pl. 1: 46. 1753.

Illustrated
Synonyms: Cyperus flavescens var. poiformis (Pursh) Fernald Cyperus poiformis (Linnaeus) Reichenbach Pycreus flavescens
Treatment appears in FNA Volume 23. Treatment on page 162. Mentioned on page 142.

Herbs, annual, cespitose. Culms trigonous, (2–) 4–30 cm × 0.4–2 mm, glabrous. Leaves 1–5, (blades often absent, base of culm with 1 reddish sheath bearing minute blade tooth 1–2 mm), (3–) 10–18 cm × (0.5–) 1.5–2 (–2.6) mm. Inflorescences: spikes 1–3, ovoid or ± digitate, 10–30 × 8–26 mm; rays 1–4 (–6), 0.5–3 (–9) cm; bracts 2–3, approximately horizontal, 1–12 cm × 0.5–2.5 mm. Spikelets 1–6, compressed, oblong-lanceoloid, 5–15 × (2–) 2.3–2.8 mm; floral scales (4–) 8–24, closely imbricate, laterally yellow to yellowish-brown, margins light-brown to clear, medially green, laterally ribless, medially 2–3-ribbed, 2-keeled basally, ovate, (1.5–) 1.8–2.2 × 1.8 mm, apex obtuse. Flowers: stamens 3; anthers 0.4 mm, connectives not prolonged; styles 0.5–1 mm; stigmas 0.5–0.8 mm. Achenes jet black to reddish-brown, slightly stipitate, obovoid, 1–1.2 × 0.8 mm, apex apiculate, surface with network of rectangular longitudinally elongate cells and transverse undulations.


Phenology: Fruiting summer–early fall.
Habitat: Damp, often disturbed soils
Elevation: 0–800 m

Distribution

V23 259-distribution-map.jpg

Ont., Ala., Ark., Calif., Del., D.C., Fla., Ga., Ill., Ind., Kans., Ky., La., Md., Mass., Mich., Miss., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va., West Indies, South America, Eurasia, Africa

Discussion

North American populations have been distinguished as Cyperus flavescens var. poiformis; their taxonomic separation was not supported by M. L. Corcoran’s (1941) careful study. Plants of Mexico and Central America consistently have purplish rather than yellowish floral scales and may be recognized as C. flavescens var. piceus (Liebmann) Fernald (G. C. Tucker 1983, 1994).

Selected References

None.

Lower Taxa

None.

"shortened" is not a number.

... more about "Cyperus flavescens"
jet black +  and reddish-brown +
0.1 cm1 mm <br />0.001 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (?) +
Gordon C. Tucker* +, Brian G. Marcks* +  and J. Richard Carter * +
Linnaeus +
persistent +  and deciduous +
decurrent +
Undefined subg. Pycreus +
w--shaped +  and keeled +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
1 cm10 mm <br />0.01 m <br /> (12 cm120 mm <br />0.12 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
parallel +  and divergent +
terete +, rolled +  and plicate +
elongate +  and rectangular +
not prolonged +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
4 cm40 mm <br />0.04 m <br /> (30 cm300 mm <br />0.3 m <br />) +
scabridulous +
trigonous +
0.4mm;2mm +
Ont. +, Ala. +, Ark. +, Calif. +, Del. +, D.C. +, Fla. +, Ga. +, Ill. +, Ind. +, Kans. +, Ky. +, La. +, Md. +, Mass. +, Mich. +, Miss. +, Mo. +, N.J. +, N.Y. +, N.C. +, Ohio +, Okla. +, Pa. +, S.C. +, Tenn. +, Tex. +, Va. +, W.Va. +, West Indies +, South America +, Eurasia +  and Africa +
0–800 m +
laterally yellow +  and yellowish-brown +
folded +  and 2-keeled +
hypogynous +  and subtending +
biconvex +  and trigonous +
Damp, often disturbed soils +
subumbellate +  and capitate +
spreading +  and erect +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
3 cm30 mm <br />0.03 m <br /> (10 cm100 mm <br />0.1 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
10 cm100 mm <br />0.1 m <br /> (?) +  and 18 cm180 mm <br />0.18 m <br /> (?) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
green +, light-brown +  and clear +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
ovate;2-keeled +
with (1-)3-6(-30) bristles and/or scales +
Fruiting summer–early fall. +
2-3(-4)-carpellate +
antrorse +  and extrorse +
3 (?) +  and 1 (?) +
nearly +  and wingless +
3 cm30 mm <br />0.03 m <br /> (9 cm90 mm <br />0.09 m <br />) +
unequal +
1 +  and 4 +
0.5 cm5 mm <br />0.005 m <br /> (3 cm30 mm <br />0.03 m <br />) +
adventitious +
basal +  and proximal +
cylindric;compressed +
cylindric +
Illustrated +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
0.8 cm8 mm <br />0.008 m <br /> (2.6 cm26 mm <br />0.026 m <br />) +
loosely spicate +  and more or less digitate +
0.2 cm2 mm <br />0.002 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
oblong-lanceoloid;compressed +
2.3mm;2.8mm +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
2-3-fid +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Cyperus flavescens var. poiformis +, Cyperus poiformis +  and Pycreus flavescens +
Cyperus flavescens +
Cyperus subg. Pycreus +
species +
tuberous +, stoloniferous +  and rhizomatous +
herb +  and cespitose +