Brassica arven'sis (Sinapis'trum), Charlock, Wild Mustard. -- Europe, United States; an annual, troublesome weed; seed smoothish, dark brown, smaller and less pungent, than our official black mustard. B. olera'cea, Cabbage, Europe; leaves large, smooth, glaucous, very different from cultivated varieties. B. campes'tris; Europe, Russia, Asia. Wild annual, .3-.6 M. (1-2 degrees) high, flowers bright yellow; of this we have several cultivated varieties which give edible roots and seeds of some value, thus: (a) var. Na'pus, Turnip -- seed larger than official black mustard, 1.6-2 Mm. (1/16-12') thick, brown or black, finely pitted, slightly acrid; (b) var. Ra'pa, Rape, Colza--seed larger than mustard or turnip, 2-1.5 Mm. (1/12-1/10') thick, finely pitted, blue-black, slightly acrid; both yield a bland, yellow fixed oil under the names of turnip-seed oil and rape-seed oil; (c) var. Rutaba'ga, Swedish Turnip -- seed also small and contain oil and pungency.