Compilation
Centaurea repens

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Name

Identification
Centaurea repens L. [family ASTERACEAE ]
Related name
  • Centaurea repens

Flora

Entry for Acroptilon repens (Linnaeus) de Candolle [family COMPOSITAE]
Herbarium
Flora of North America (FNA)
Collection
Flora of North America
Resource Type
Reference Sources
Entry From
Flora of North America, Vol 19,
Names
Acroptilon repens (Linnaeus) de Candolle [family COMPOSITAE], in A. P. de Candolle and A. L. P. P. de Candolle, Prodr., 6: 663. 1838
Centaurea repens Linnaeus [family COMPOSITAE], Sp. Pl. ed., 2, 2: 1293. 1763
Acroptilon picris (Pallas ex Willdenow) C. A. Meyer [family COMPOSITAE]
C. picris Pallas ex Willdenow [family ]
Treatment Author(s)
David J. Keil
Information
Creeping roots usually dark brown or black, with scaly adventitious buds. Stems ± cobwebby-tomentose. Leaves: basal and proximal cauline often deciduous by flowering, blades oblong, 4–15 cm; mid and distal linear to linear-lanceolate or oblong, 1–7 cm. Involucres 9–17 mm, loosely cobwebby. Phyllaries: apices of inner acute or acuminate, densely short-pilose. Corollas 11–14 mm, tubes 6.5–7.5 mm, throats 2–3.5 mm, lobes 3–3.5 mm. Cypselae ivory to grayish or brown, 2–4 mm; pappus bristles white, 6–11 mm. 2n = 26.
Phenology
mar-may (spring), jun-aug (summer), sep (fall)
Altitude range
0–2300 m;
Distribution
Mexico (Baja California)c Asia.USA Ariz.USA Calif.USA Colo.USA IdahoUSA IowaUSA Kans.USA Minn.USA Mont.USA Nebr.USA Nev.USA N.Mex.USA N.Dak.USA Okla.USA Oreg.USA S.Dak.USA Tex.USA UtahUSA Wash.USA Wyo.Canada Alta.Canada B.C.Canada Man.Canada Ont.Canada Sask.
Discussion
Acroptilon repens has been reported also from Arkansas, Illinois, Indiana, Kentucky, Louisiana, Michigan, Missouri, New York, Ohio, Virginia, and Wisconsin; I have not seen specimens from those states.
Acroptilon repens is a serious weed pest, especially in the western United States. It is a strong competitor in infested areas, often forming dense colonies, and has allelopathic effects on other plants growing nearby. It is very difficult to control or eradicate once it becomes established. It reproduces vigorously from seed and spreads from adventitious buds borne on deep-seated runner roots. Root fragments readily regenerate as new individuals after cultivation. In addition, Russian knapweed is very poisonous to horses, causing neurological symptoms. Because of its bitter taste, it is usually avoided by grazing animals, and consequently it tends to spread when more palatable plants are consumed.
Native/Introduced
introduced;

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