Cruciferae

Cruciferae, a large family of thalamifloral dicotyledonous plants, mostly herbs with watery juice which is often pungent or even acrid, though never poisonous. They have generally simple, scattered, exstipulate leaves, and yellow, white, or rarely red flowers arranged in ebracteate and often corymbose racemes. There are two pairs of sepals to each flower, the outer pair antero-posterior, the inner ones often pouched at the base. The four diagonally-arranged hypogynous petals being arranged like a cross, give its name to the order, which, however, corresponds almost exactly with Linnaeus's fifteenth class, the Tetradynamia, so called on account of the stamens being tetradynamous - six in number, that is, the two outer or lateral ones shorter, the four inner ones being longer. These four long stamens apparently represent two antero-posterior stamens, which at an early stage undergo branching or collateral chorisis (q.v.). There are two carpels, which are united into a dry pod-like fruit known as a siliqua (q.v.). It is two-chambered, owing to the formation of a septum by the ingrowth of the carpels from their parietal placentas. The fruit is often compressed, either in the direction of this septum or at right angles to it, and is sometimes shortened, when it is termed a silicle. The seeds are generally small, and are exalbuminous, the order being divided into tribes in accordance with the various ways in which the cotyledons (q.v.) are folded with reference to the radicle. The order includes the genus Brassica (q.v.), the cabbages and mustards, sea-kale, cresses (q.v.), radishes, stocks, wallflowers, rockets, and woad. Many plants belonging to it have oily seeds, as the rape and the mustard, for example.