4. Linum usitatissimum Linnaeus, Sp. Pl. 1: 277. 1753.
亚麻 ya ma
Linum humile Miller.
Annuals 30-120 cm tall. Stems simple, cylindric, erect, woody at base, apically corymbosely branched. Leaves alternate, linear, linear-lanceolate, or lanceolate, 2-4 cm × 1-5 mm, 3(or 5)-veined from base, base attenuate, apex acute. Flowers axillary, solitary or in broad cymes, 15-20 mm in diam. Pedicel 1-3 cm, erect. Sepals ovate to ovate-lanceolate, 5-8 mm, 3(or 5)-veined from base, nonglandular, margin entire or ciliate, apex acute to acuminate. Petals blue, rarely white or red, obovate, 0.8-1.2 cm. Styles distinct; stigma linear-clavate. Capsule globose, 6-9 mm in diam., septicidal, with 10 seeds. Seeds brown, oblong, flattened, 3.5-4 mm. Fl. Jun-Aug, fr. Jul-Oct. 2n = 30.
Cultivated throughout China except Hainan and Taiwan, sometimes naturalized [origin uncertain but possibly the Mediterranean region and/or parts of W Asia and W Europe, widely cultivated].
This species is used for fiber and oil.