Morocco knapweed

Centaurea muricata Linnaeus, Sp. Pl. 2: 918. 1753; Amberboa muricata (Linnaeus) de Candolle; Cyanopsis muricata (Linnaeus) Dostál; Volutarella muricata (Linnaeus) Bentham & Hooker f.

Leaves: proximal oblanceolate, margins denticulate to deeply pinnatifid, distal smaller, linear, ± entire or lobed, faces villous with septate hairs, minutely resin-gland-dotted. Heads 3–5 cm diam. Peduncles 5–15 cm, distally leafless, finely arachnoid-tomentose, especially near tips. Involucres 15–18 mm. Phyllaries in 5–7 series, minutely spinulose-serrulate, finely pilose, outer and mid ovate, appressed, dark-margined, abruptly tipped by spreading or reflexed, flattened spine tips 3–5 mm, inner lanceolate, with erect or flaring, flattened, ± spineless tips. Florets: corolla lobes of sterile 10–15 mm, spreading; corollas of fertile 13–14 mm, tubes 5–6 mm, throats 2–4 mm, lobes 5–6 mm. Cypselae pale gray-brown, scars with cartilaginous rims; pappi of irregularly toothed scales 1–2.5 mm, outer shorter and narrower than inner. 2n = 24 (n Africa, as Cyanopsis muricata).

Flowering Mar–Jun. Disturbed sites, sparingly established, in coastal regions, probably escaped from cultivation; 0–100 m; introduced; Calif.; sw Europe; n Africa.