Centaurea calcitrapa L.
An almost hairless perennial. Stems ascending or erect, up to 60 cm long; branching from the base. Leaves rough, pinnatifid with narrow, serrated bristle-pointed lobes. Upper leaves sessile, the lower ones on long stalks. Flower heads pink or pale purple, solitary, terminal and in the axils, practically sessile, about 1 cm across; ray florets absent. Florets glandular, 1.8 cm long. Involucre up to 1.5 cm long, with many rows of overlapping, spiny bracts. Outer and middle bracts with a spreading, yellowish, apical appendage up to 3 cm long, forming a star; and with up to 3 pairs of lateral spines around their base. Achenes about 3 mm long, without a pappus.
Local: Very rare in Gibraltar, only found on Windmill Hill Flats.
Global: Found throughout most of Europe, the Mediterranean region, and west and south-west Asia.
Flowers from May, June to July (August).
Grows on dry, stony ground, waysides, waste ground, uncultivated fields.