Centaurea sulphurea

Annuals, 10-100 cm. Stems simple to openly branched, branches ascending, villous to hispid with septate hairs and loosely tomentose. Leaves ± villous to hispid with septate hairs, minutely resin-gland- dotted; basal winged-petiolate. blades oblong to oblanceolate, 10-15 cm, margins pinnately lobed, lobes acute, finely dentate; cauline sessile, long-decurrent with narrow wings, linear-oblong to oblanceolate, 1-6 cm, entire or distally serrate with short, spine-tipped teeth. Heads disciform, borne singly or in open, few-headed corymbiform arrays, long-pedunculate. Involucres ovoid, 12-30 mm, distally constricted. Principal phyllaries: bodies greenish or stramineous, ovate to elliptic, glabrous, appendages spreading to reflexed, brown to blackish purple, each with palmately radiating cluster of spines, central spine stout, 1-2.5 cm, base dark brown to black, distally stramineous. Inner phyllaries: appendages acute or spine-tipped. Florets many; corollas yellow, all ± equal, 25-35 mm; corollas of sterile florets slender, inconspicuous. Cypselae dark brown, 5-8 mm, glabrous; pappi of many, brown to blackish, unequal bristles 6-7 mm. 2n = 24.

Flowering spring-summer (May-Jul). Disturbed sites, grasslands, woodlands, pastures, roadsides; 0-300 m; Calif.; sw Europe.