Centaurea calcitrapa

Linnaeus

Sp. Pl. 2: 917. 1753.

Common names: Purple star-thistle caltrops chausse-trappe centaurée chausse-trappe
Introduced
Treatment appears in FNA Volume 19. Treatment on page 191. Mentioned on page 183, 192.

Annuals, biennials, or short-lived perennials, 20–100 cm. Stems 1–several, often forming rounded mounds, puberulent to loosely tomentose. Leaves puberulent to loosely gray-tomentose, becoming ± glabrous, minutely resin-gland-dotted; proximal leaves petiolate, blades 10–20 cm, 1–3 times pinnately dissected, rosette with central cluster of spines; mid sessile, not decurrent, blades ovate, usually less than 10 cm, narrowly lobed; distal blades linear to oblong, entire to shallowly lobed. Heads disciform, borne singly or in leafy cymiform arrays, sessile or short-pedunculate. Involucres ovoid, 15–20 × 6–8 mm. Principal phyllaries: bodies greenish or stramineous, ovate, scarious-margined, appendages stramineous, spiny-fringed at base, each tipped by a stout spreading spine 10–25 mm. Inner phyllaries: appendages truncate, spineless. Florets 25–40; corollas purple, all ± equal, 15–24 mm; sterile corollas slender. Cypselae white or brown-streaked, 2.5–3.4 mm, glabrous; pappi 0.2n = 20.


Phenology: Flowering summer–autumn (Jun–Nov).
Habitat: Pastures, fields, roadsides
Elevation: 0–1700 m

Distribution

V19-221-distribution-map.gif

Ont., Ala., Ariz., Calif., D.C., Fla., Ga., Ill., Iowa, Md., Mass., N.J., N.Mex., N.Y., Oreg., Pa., Utah, Va., Wash., Europe, Africa

Discussion

Centaurea calcitrapa is native to southern Europe and northern Africa. It is listed as a noxious weed in Arizona, California, Nevada, New Mexico, Oregon, and Washington. These plants are unpalatable and increase on rangelands as more desirable forage plants are consumed. Dense stands are impenetrable because of the vicious spines on the mature involucres.

Centaurea ×pouzinii de Candolle, an apparently stabilized hybrid between Centaurea aspera (2n = 22) and C. calcitrapa (2n = 20), has been reported from California. A chromosome count of 2n = 42 has been reported from California material of this nothospecies (A. M. Powell et al. 1974). Centaurea ×pouzinii can be distinguished from C. calcitrapa by its shorter spines and by cypselae with a short pappus. Reports of C. calcitrapoides Linnaeus from North America are apparently based on this hybrid.

Selected References

None.

Lower Taxa

None.

"fine" is not a number."fine" is not a number.

... more about "Centaurea calcitrapa"
with fine , 1-celled hairs +  and glabrous +
scarious +
spineless +, tipped +  and spiny-fringed +
erect;spreading +
less dentate or fringed linear +  and ovate +
cymiform +  and leafy +
indeterminate +  and determinate +
David J. Keil +  and Jörg Ochsmann +
Linnaeus +
decurrent +
Asteraceae tribe Cynareae +
compound +  and simple +
lobed;ovate +
1-3 times pinnately dissected rosette +
0 cm0 mm <br />0 m <br /> (10 cm100 mm <br />0.1 m <br />) +
scarious-margined +
stramineous +  and greenish +
10-nerved or 20-nerved +  and rugose +
barbed +  and smooth +
Purple star-thistle +, caltrops +, chausse-trappe +  and centaurée chausse-trappe +
actinomorphic +
radial +  and bilateral +
white +  and blue pink purple or yellow +
inconspicuous +
1.5 cm15 mm <br />0.015 m <br /> (2.4 cm24 mm <br />0.024 m <br />) +
brown-streaked +  and white +
compressed +  and barrel--shaped +
fertile +  and bisexual +
Ont. +, Ala. +, Ariz. +, Calif. +, D.C. +, Fla. +, Ga. +, Ill. +, Iowa +, Md. +, Mass. +, N.J. +, N.Mex. +, N.Y. +, Oreg. +, Pa. +, Utah +, Va. +, Wash. +, Europe +  and Africa +
0–1700 m +
glandular-punctate +
puberulent +, strigose +, villous +, tomentose +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Pastures, fields, roadsides +
short-pedunculate +  and sessile +
in leafy cymiform arrays +  and singly +
indeterminate +
each +  and sessile +
1.5 cm15 mm <br />0.015 m <br /> (2 cm20 mm <br />0.02 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
resin-gland-dotted +, glabrous +, puberulent +  and loosely gray-tomentose +
acute +  and linear-oblong +
entire +  and dentate +
usually lobed +  and dissected +
rounded +
2-carpellate +
persistent +
Flowering summer–autumn (Jun–Nov). +
papillate +  and smooth +
distinct +  and fused +
flat;convex +
exalbuminous +
Introduced +
1 cm10 mm <br />0.01 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
branched +  and simple +
spreading +, ascending +  and erect +
1 +  and several +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
Acosta +, Cnicus +, Grossheimia +, Jacea +  and Leucacantha +
Centaurea calcitrapa +
Centaurea +
species +
perennial +, short-lived +, biennial +  and annual +
tomentose +  and glabrous +
not decurrent +
20 cm200 mm <br />0.2 m <br /> (100 cm1,000 mm <br />1 m <br />) +
tree +, vine +, shrub +  and subshrub +
15 +, 13 +, 12 +, 11 +, 10 +, 9 +  and 8 +