蓝花矢车菊 lan hua shi che ju

Centaurea cyanus Linnaeus, Sp. Pl. 2: 911. 1753; C. cyanocephala Velenovský.

Herbs 30-70 cm tall, annual or rarely biennial. Stem erect, branched from middle, rarely unbranched; stem and branches grayish white, thinly arachnoid floccose. Leaves abaxially grayish white and sparsely tomentose, adaxially green to grayish green and sparsely arachnoid. Basal and lower stem leaves petiolate; leaf blade narrowly elliptic-oblanceolate to lanceolate, undivided or lyrately pinnatisect; lateral segments 1-3 pairs, narrowly elliptic-lanceolate, linear-lanceolate, or linear, margin entire; terminal segment narrowly elliptic-oblanceolate, margin serrulate. Middle stem leaves sessile, broadly linear to linear-lanceolate, rarely with lateral laciniae near base, 4-9 × 0.3-0.8 cm, base attenuate, margin entire, apex acute. Upper stem leaves similar in shape to middle stem leaves, decreasing in size upward. Capitula few to many, corymbose or paniculate. Involucre ellipsoid, 5-13 mm in diam., sparsely arachnoid. Phyllaries in ca. 6 rows, appendaged; appendage brownish or white, scarious, fimbriate; outer and middle phyllaries elliptic to narrowly elliptic, 3-6 × 2-4 mm; inner phyllaries elliptic, 10-11 × 3-4 mm. Outer florets blue, white, red, or purple, longer than inner florets; inner florets bluish violet. Achene ellipsoid, ca. 3 mm, striate, sparsely pilose-pubescent. Pappus elements in several rows, scabrid; outer pappus elements bristlelike, 2-3 mm; inner pappus elements bristlelike to narrowly scalelike, 1-2 mm. Fl and fr. Feb-Aug. 2n = 24, 48*.

Occasionally naturalized in at least Qinghai and Xinjiang [native to Europe].

Cyanus segetum is widely grown in China as an ornamental. The whole plant is used medicinally, and the seed oil can be used for soap making.