17. BRÁSSICA (Brassica and Sinàpis), Tourn.
Pod linear or oblong, nearly terete or 4-sided, with a stout 1-seeded beak or a rigid style; valves 1--5-nerved. Seeds globose, 1-rowed. Cotyledons incumbent, folded around the radicle.--Annuals or biennials, with yellow flowers. Lower leaves mostly lyrate, incised, or pinnatifid. (The Latin name of the Cabbage. Sinapis is the Greek σίναπι, which is said to come from the Celtic _nap_, a turnip.)
B. SINAPÍSTRUM, Boiss. (or SINÀPIS ARVÉNSIS, L., the English CHARLOCK), with knotty pods, fully one third occupied by a stout 2-edged beak (which is either empty or 1-seeded), the upper leaves barely toothed, is a noxious weed in grain-fields, from N. Eng. to Penn. and N. Y. westward. (Adv. from Eu.)
B. (or SINÀPIS) ÁLBA. (WHITE MUSTARD.) Pods bristly, ascending on spreading pedicels, more than half its length occupied by the sword-shaped 1-seeded beak; leaves all pinnatifid; seeds pale. (Cult. and adv. from Eu.)
B. (or SINÀPIS) NÌGRA, Koch. (BLACK MUSTARD.) Pods smooth (½´ long), 4-cornered (the valves only 1-nerved), erect on appressed pedicels forming a slender raceme, tipped with a stout persistent style; seeds dark brown, smaller and more pungent than in the last; lower leaves with a large terminal lobe and a few small lateral ones.--Fields and waste places. (Adv. from Eu.)
B. CAMPÉSTRIS, L., in the form of the RUTABAGA and the TURNIP, sometimes persists a year or two in neglected grounds.
Pod obcordate-triangular, flattened contrary to the narrow partition; the valves boat-shaped, wingless. Seeds numerous. Cotyledons incumbent.--Annuals; flowers small, white. (Name a diminutive of _capsa_, a box.)
C. BURSA-PASTÒRIS, Moench. Root-leaves clustered, pinnatifid or toothed; stem-leaves arrow-shaped, sessile.--Waste places; the commonest of weeds. April--Sept. (Nat. from Eu.)
Pod orbicular, obovate, or obcordate, flattened contrary to the narrow partition, the midrib or keel of the boat-shaped valves extended into a wing. Seeds 2--8 in each cell. Cotyledons accumbent. Petals equal.--Low plants, with root-leaves undivided, stem-leaves arrow-shaped and clasping, and small white or purplish flowers. (Ancient Greek name, from θλάω, _to crush_, from the flattened pod.)