Centaurea macrocephala

Muss. Puschk. ex Willd.
Sp. Pl., ed. 4 [Willdenow] 3(3): 2298 (-2299). 1803 [Apr-Dec 1803].
Common names: Globe centaurea big-head knapweed yellow bachelor’s button or cornflower centaurée à gros capitules
Introduced
Synonyms: Grossheimia macrocephala (Puschkarew ex Willdenow) Sosnowsky & Takhtajan
Treatment appears in FNA Volume 19. Treatment on page 185. Mentioned on page 183.

Perennials, 50–170 cm. Stems usually several, erect, unbranched or sparingly branched distally, villous with septate hairs, thinly arachnoid-tomentose, fistulose proximal to heads. Leaves short-villous and thinly arachnoid, ± glabrate, resin-gland-dotted; basal and proximal cauline petiolate, blades oblanceolate to narrowly ovate, 10–30 cm, margins entire or shallowly dentate; cauline sessile, shortly decurrent, not much smaller except those crowded proximal to heads, blades lanceolate to ovate, 5–10 cm, entire, often ± undulate, apices acute. Heads disciform or weakly radiant, borne singly, sessile, closely subtended by clusters of reduced leaves. Involucres ovoid to hemispheric, 25–35 mm. Phyllaries: bodies pale green or stramineous, ovate or broadly lanceolate, glabrous, appendages erect to spreading, brown, scarious, abruptly expanded, 1–2 cm wide, ± covering phyllary bodies, lacerate fringed, sometimes tipped by weak spines 1–2 mm, glabrous. Florets many; corollas yellow; corollas of sterile florets slightly expanded, ca. 4 mm; corollas of disc florets ca. 3.5 mm. Cypselae 7–8 mm; pappi of many setiform scales (“flattened bristles”), 5–8 mm. 2n = 18 (Russia).


Phenology: Flowering summer (Jun–Sep).
Habitat: Garden escape in meadows, grassy clearings
Elevation: 400–2000 m

Distribution

V19-209-distribution-map.gif

Introduced; Ont., Que., Colo., Mich., Wash., Wis., e Europe, w Asia.

Discussion

Although Centaurea macrocephala is cultivated as an ornamental and for cut flowers in many areas, it has been declared a noxious weed by the state of Washington because of its potential status as an invader.

Selected References

None.

Lower Taxa

None.

... more about "Centaurea macrocephala"
David J. Keil +  and Jörg Ochsmann +
Muss. Puschk. ex Willd. +
Asteraceae tribe Cynareae +
Globe centaurea +, big-head knapweed +, yellow bachelor’s button or cornflower +  and centaurée à gros capitules +
Ont. +, Que. +, Colo. +, Mich. +, Wash. +, Wis. +, e Europe +  and w Asia. +
400–2000 m +
Garden escape in meadows, grassy clearings +
Flowering summer (Jun–Sep). +
Sp. Pl., ed. 4 [Willdenow] +
1753 +  and 1754 +
Introduced +
Grossheimia macrocephala +
Centaurea macrocephala +
Centaurea +
species +