Centaurea

[NL. See Centaury.]
(Bot.) A large genus of composite plants, related to the thistles and including the cornflower or bluebottle (Centaurea Cyanus) and the star thistle (C. Calcitrapa).

Sen-tor'ree-a. A genus of chiefly Eurasian herbs comprising over 400 species.

Description
Leaves basal or alternate on stems, entire to divided, not spiny. Flowerheads contain tubular flowers; along the edge, they are often expanded and raylike. Below the head is a series of overlapping bracts.

How to Grow
The daisy-type Centaurea should be direct seeded in early spring where growing seasons are short, and in late summer through fall where winters are mild. The foliage types should be started very early indoors. Set out when plants are large. C. americana and C. Cyanus prefer cool weather, while C. Cineraria needs a warm growing season.

Centaurea americana
Basket-Flower . 4-6 ft. (1.2-1.8 m) high. Heads 4-5 in. (10.0-12.5 cm) wide, rose to pink, the marginal flowers raylike, hence the head set as though in a shallow basket. Fringed bracts below the head. Cen. U.S. to Mexico. Hardy annual.

Centaurea Cineraria
Dusty Miller . 1-3 ft. (30-90 cm) high, grown for its prominently white-felty foliage. Leaves to 1 ft. (30 cm) long, parted into blunt but narrow lobes. S. Italy. Half-hardy annual.

Centaurea Cyanus
Bachelor's Button ; Cornflower ; Bluebottle ; Ragged Sailor ; Blue Bonnets . Sprawling annual, 1-2 ft. (30-60 cm) high. Heads 1 Ɖ in. (4 cm) wide, typically pale blue, or purple, pink, or white in horticultural forms. S. Europe. Double-flowered forms in nearly all colors. Hardy annual.

The botanical name for cornflower, mountain bluet, or bachelor's button.