Cyperus difformis

Linnaeus

Cent. Pl. II, 6. 1756.

Common names: Variable flatsedge
IntroducedIllustrated
Synonyms: Cyperus lateriflorus Torrey
Treatment appears in FNA Volume 23. Treatment on page 156. Mentioned on page 143, 157.

Herbs, annual, cespitose. Culms 1–15, trigonous, 7–30 cm × 1.2–2.5 mm, soft (flattened in pressing), glabrous. Leaves 2–7, flat, (2–) 7–22 cm × 2.2–4 mm. Inflorescences: heads dense, 7–17 mm diam.; when rays short, heads sessile or nearly so, then densely irregularly lobate, 12–35 mm diam.; rays 1–5, 2–32 mm; bracts 2–4, longest bract erect or nearly so, appearing as continuation of culm, other bracts horizontal to ascending, 1–22 cm × 0.5–3.5 mm, margins and keel minutely scabridulous. Spikelets 30–120, greenish brown to purplish brown, oblongellipsoid, compressed, (2–) 3–5 (–6) × 0.8–1.2 mm; floral scales (6–) 12–20 (–30), laterally clear margins, stramineous to deep purple, medially greenish, stramineous, or purplish, laterally ribless, medially 3-ribbed, obovate to orbiculate, 0.6–0.8 × 0.6–0.8 mm, apex mucronulate. Flowers: stamens 1 or 2; anthers ovoid-ellipsoid, 0.1 mm, connective not prolonged; styles 0.1 mm; stigmas 0.1–0.3 mm. Achenes light-brown, obovoidellipsoid, 0.6–0.8 × 0.3–0.4 mm (as long as subtending scale), base cuneate, apex obtuse, apiculate, surfaces finely reticulate, papillose.


Phenology: Fruiting summer.
Habitat: Disturbed, muddy soils, shallow waters
Elevation: 0–1000 m

Distribution

V23 243-distribution-map.jpg

Introduced; Ala., Ariz., Calif., Fla., Ga., Idaho, Ky., La., Miss., N.J., N.Mex., N.C., Oreg., Pa., S.C., Tenn., Tex., Va., Mexico, West Indies (Puerto Rico), Central America (Nicaragua), Central America (Panama), South America, Eurasia, Indian Ocean Islands, Pacific Islands, Australia

Discussion

Cyperus difformis is naturalized in the New World and native to the Old World, where it ranges from southern Europe to southern Africa and eastward to Southeast Asia and Australia.

Selected References

None.

Lower Taxa

None.
... more about "Cyperus difformis"
light-brown +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
terete;planoconvex;terete;planoconvex;trigonous +
0.3mm;0.4mm +
ovoid-ellipsoid +
0.1 cm1 mm <br />0.001 m <br /> (?) +
Gordon C. Tucker* +, Brian G. Marcks* +  and J. Richard Carter * +
Linnaeus +
shortened +
persistent +  and deciduous +
cuneate +
w--shaped +  and keeled +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
1 cm10 mm <br />0.01 m <br /> (22 cm220 mm <br />0.22 m <br />) +
horizontal +  and ascending +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
parallel +  and divergent +
terete +, rolled +  and plicate +
Variable flatsedge +
not prolonged +
7 cm70 mm <br />0.07 m <br /> (30 cm300 mm <br />0.3 m <br />) +
scabridulous +
trigonous +
1.2mm;2.5mm +
Ala. +, Ariz. +, Calif. +, Fla. +, Ga. +, Idaho +, Ky. +, La. +, Miss. +, N.J. +, N.Mex. +, N.C. +, Oreg. +, Pa. +, S.C. +, Tenn. +, Tex. +, Va. +, Mexico +, West Indies (Puerto Rico) +, Central America (Nicaragua) +, Central America (Panama) +, South America +, Eurasia +, Indian Ocean Islands +, Pacific Islands +  and Australia +
0–1000 m +
folded +  and 2-keeled +
hypogynous +  and subtending +
biconvex +  and trigonous +
Disturbed, muddy soils, shallow waters +
nearly +  and sessile +
1.2 cm12 mm <br />0.012 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
subumbellate +  and capitate +
spreading +  and erect +
scabridulous +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
2 cm20 mm <br />0.02 m <br /> (7 cm70 mm <br />0.07 m <br />) +
7cm +  and 22cm +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
nearly +  and erect +
stramineous +  and deep purple medially greenish stramineous or purplish +
0.6mm;0.8mm +
scabridulous +
obovate;orbiculate +
0.6mm +  and 0.8mm +
with (1-)3-6(-30) bristles and/or scales +
Fruiting summer. +
2-3(-4)-carpellate +
antrorse +  and extrorse +
3 (?) +  and 1 (?) +
Cent. Pl. II, +
unequal +
1 +  and 5 +
0.2 cm2 mm <br />0.002 m <br /> (3.2 cm32 mm <br />0.032 m <br />) +
adventitious +
basal +  and proximal +
cylindric;compressed +
cylindric +
W2 +, W1 +, Introduced +  and Illustrated +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
greenish brown +  and purplish brown +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
30 +  and 120 +
compressed +
0.8mm;1.2mm +
2 (?) +  and 1 (?) +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
2-3-fid +
0.1 cm1 mm <br />0.001 m <br /> (?) +
papillose +
Cyperus lateriflorus +
Cyperus difformis +
Cyperus subg. Pycnostachys +
species +
tuberous +, stoloniferous +  and rhizomatous +
herb +  and cespitose +