334 THE KINDS OF PLANTS 



Cabbage, cauliflower, and turnip also belong to this genus. The three fol- 

 lowing are common weeds introduced from Europe. 



B. nigra, Koch. Black mustard. Fig. 459. Leaves pinnatitid, some- 

 what hairy: pod short, strongly 4-angled, not hairy. Mustard (flour) comes 

 largely from this species. 



B, dlba, Boiss. White mustard. Leaves pinnatifid and rough- 

 hairy: pods rather slender, hairy, but only the lower part seed- 

 bearing. 



B. Sinapistrum, Boiss. Charlock. Leaves strongly toothed: 

 pod knotty, hairy or smooth, the upper third indehiscent and 

 2-edged. 



2. BABBAII£;A. Winter-cress. 



Low herbs, blooming in early spring, with many small light 



yellow flowers, and lyrate leaves with the terminal division much the 



largest: pod cylindrical or somewhat 4-angled, the valves having a 



strong midvein: seeds a single row. 



459. B. vulg£lris, R. Br. Common winter cress. Yellow rocket. 



Brassica Biennial, about 1 ft. high, with smooth foliage and flowers in elon- 



nigra. gating clusters: lower leaves lyrate, upper ones cut or merely 



toothed. Low grounds. 



3. MATTHlOLA. Stock. Gilliplower. 



Cultivated garden or house plants from Europe: stems and leaves hoary- 

 pubescent: flowers showy, single or double, of many colors, fragrant, in 

 terminal racemes: stigma deeply 2-lobed: silique nearly cylindrical, with 

 prominent midrib on each of the two valves: seeds winged. 



M, incitiia, Br. Biennial or perennial with stout, rather woody stem: 

 l":ives lanceolate, entire: flowers white, varied shades of red, purple, etc. 

 ]\Iuch grown in gardens and greenhouses. 



4. AKABIS. Rock Cress. 



Mostly very small herbs with purple or white flowers: stems leafy: rad- 

 ical leaves spatulate, the stem leaves sessile: siliques very narrow, elongated, 

 flat, the valves smooth, keeled or one-nerved in the middle, or veined length- 

 wise: seeds in 1 or 2 rows in each cell, flattened, usually margined or 

 winged. 



A. Canadensis, Linn. Sickle-pod. Biennial with stems erect, 1-3 ft.: 

 leaves lanceolate, pointed at both ends, simple, toothed or entire, sessile, 

 pubescent: flowers small, white, petals twice as long as sepals: pods long, 

 flat, sickle-shaped, pendent on hairy pedicels: seeds broadly winged. Com- 

 mon in woods and rocky ravines. 



A. perfolid,ta, Lam. Biennial; tall, 2-4 ft., glaucous above, but pubescent 

 at base, with many stem leaves, ovate-lanceolate, sessile, sagittate-clasping 

 at base; petals yellowish white, scarcely longer than the calyx: pods narrow, 

 erect: seeds in 2 rows, marginless. Fields and rocky places. 



