Singleflower knapweed

Centaurea uniflora is a perennial herb of the daisy family (Asteraceae) restricted to the southwestern Alps, the Maritime Alps and the northern Apennines of France and Italy, where it grows in alpine and subalpine meadows on calcareous to siliceous soils. It forms low tufts with a stout, woody rootstock and erect, simple stems 10–35 cm tall, densely covered with whitish woolly hairs. The basal and lower stem leaves are linear-lanceolate, 5–15 cm long, with entire to obscurely toothed margins and a tomentose, greyish-green appearance; the upper leaves become smaller and bract-like. Each stem bears a single, conspicuous terminal flower head 3–5 cm across, with an involucre of broad, pale brown bracts whose tips are produced into a brown-black, comb-like fringe. All florets are tubular and bright purplish-pink to violet, with the outer ones enlarged and sterile in radiant form. The achenes are small, brownish, and topped with a short pappus of bristles. Flowering occurs in summer.