Linnaeus, Sp. Pl. 1: 448. 1753.
annual or biennial, (20-)40-100(-150) cm, glabrous.
erect, simple or branched.
(cauline subsessile dis-tally); blade oblong-spatulate, 5-10(-15) × 0.5-2 cm, margins entire or subentire (flat or crispate), surfaces glabrous or, sometimes, with 1-2 conical glands basally.
10-50 cm; bracts persistent, lanceolate-attenuate, 2-3.5 mm (4-5 mm in fruit).
sepals persistent, 4, not reflexed in fruit, lanceolate-ovate, 1-2.5 mm; petals 4, yellowish, 2-4 mm, rounded-clawed, adaxial ones irregularly lobed; stamens 20-40; filaments persistent, 2-3 mm, glabrous; intrastaminal nectary-discs glabrous; anthers 0.5-0.6 mm; placenta forked distally.
erect, 3-carpelled, ovoid to subglobose, 3-5 × 4-6 mm, apically 3-toothed, usually glabrous.
0.6-1 mm, glossy, smooth.
= 24, 26.
Flowering (Jan-)Mar-Sep(-Dec). Waste ground, roadsides, fields, railway yards, ballast ground, basic and sandy soils; 0-2900 m; introduced; B.C., N.S.; Calif., Colo., Conn., Del., Ill., Ind., Iowa, Md., Mass., Mo., N.J., N.Y., Ohio, Oreg., Pa., R.I., Tex., Wash.; Europe; sw Asia; n Africa; n Atlantic Islands; introduced also in n, c Mexico.
is a traditional Old World dye plant, used since Roman times. It contains a high amount of the flavonoid luteolin, which yields one of the most brilliant yellow dyes. When combined with woad (
, Brassicaceae), it yields "Saxon Green." In the nineteenth century
was widely growing, which favored its spreading through many parts of the world; today, it has fallen into disuse. Its potential as a crop for natural dyeing of textiles is being re-evaluated. It is also grown as an ornamental; the appealing rosettes of yellowish green leaves acquire a reddish blush in cool weather.