Annual or perennial often paniculately or corymbosely branched herbs. Leaves alternate or occasionally opposite, without stipules but sometimes with stipular glands, mostly narrow, entire or serrulate, sometimes ciliate or glandular-margined. Sepals 5, persistent or deciduous, all of them or only the inner ones with gland-tipped teeth Petals 5, yellow or white, unappendaged but sometimes pubescent within near the entire base. Stamens 5; filaments united at the base, the free portions abruptly or gradually dilated at the base, not accompanied by staminodia, or rarely with a short staminodium in each sinus. Gynoecium 5-carpellary, or rarely 2-carpellary, sometimes cartilaginous at the base; styles filiform, distinct or united; stigmas distinct, terminal, capitate. Capsule ovoid or depressed, 5-ceHed, or rarely 2-celled and with firm septa, or completely or incompletely 10-celled by false septa, the carpels not ribbed on the back. Seeds flattened, often lunate. [Greek, referring to the medicinal qualities of some of the species.]

About 70 species of wide geographic distribution. Type species: Linum cathàrticum L. Styles distinct.