Centaurea melitensis |
Centaurea virgata |
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croix de malte, Maltese knapweed, Maltese star thistle or centaury, Maltese star-thistle, Napa thistle, tocalote |
squarrose knapweed |
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Habit | Annuals, 10–100 cm, herbage loosely gray-tomentose and villous with jointed multicellular hairs, sometimes minutely scabrous, minutely resin-gland-dotted. | |
Stems | 1–few, few–many branched distally. |
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Leaves | basal and proximal cauline petiolate or tapering to base, usually absent at anthesis, blades oblong to oblanceolate, 2–15 cm, margins entire to dentate or pinnately lobed; cauline long-decurrent, blades linear to oblong or oblanceolate, 1–5 cm, entire or dentate. |
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Involucres | ovoid, 10–15 mm, loosely cobwebby-tomentose or becoming glabrous. |
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Florets | many; corollas yellow, those of sterile florets 10–12 mm, slender, inconspicuous, those of fertile florets 10–12 mm. |
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Inner phyllaries | appendages entire, acute or spine-tipped. |
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Heads | disciform, 1–few at branch tips, borne singly or in open leafy corymbiform arrays, sometimes clustered in distal axils, sessile or pedunculate. |
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Cypselae | dull white or light brown, ca. 2.5 mm, finely hairy; pappi of many white, unequal, stiff bristles 2.5–3 mm. |
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Principal | phyllaries: bodies ± stramineous, ovate, appendages purplish, spiny-fringed at base, each tipped by slender spine 5–10 mm. |
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2n | = 24. |
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Centaurea melitensis |
Centaurea virgata |
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Phenology | Flowering mostly spring–summer (Apr–Jul). | |
Habitat | Roadsides, fields, pine-oak woodlands, chaparral, agricultural areas | |
Elevation | 0–1500 m (0–4900 ft) | |
Distribution |
AL; AZ; CA; GA; ID; IL; MA; MO; MS; NJ; NM; NV; OR; PA; TX; UT; WA; WI; BC; Mexico (Baja California); Europe; Asia; Africa [Widely introduced]
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CA; CO; MI; NV; OR; UT; WY; w Asia
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Discussion | Centaurea melitensis is native to the Mediterranean region. It is listed as a noxious weed in New Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (1 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 193. | FNA vol. 19, p. 191. |
Parent taxa | Asteraceae > tribe Cardueae > Centaurea | Asteraceae > tribe Cardueae > Centaurea |
Sibling taxa | ||
Subordinate taxa | ||
Name authority | Linnaeus: Sp. Pl. 2: 917. (1753) | Lamarck: in J. Lamarck et al., Encycl. 1: 670. (1785) |
Web links |
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