104 KEY AND FLORA 
1. B. alba Boiss. WuitE Mustarpv. Stem 2-5 ft. high, with 
reflexed hairs. Upper leaves pinnately cut. Pods borne on spreading 
pedicels, bristly, with a sword-shaped, 1-seeded beak occupying more 
than half their length. Seeds pale. Cultivated from Europe and 
introduced. to some extent. 
2. B. arvensis Ktze. Cuartock. Stem 1-2 ft. high; it and the 
ibaves rough-hairy. Upper leaves rhombic, barely toothed. Flowers 
3-} in. across, somewhat corymbed, bright yellow. Pods knotty, 
spreading, at least 1 of each consisting of a 2-edged, 1-seeded beak. 
A showy, troublesome weed in grain fields. Naturalized from Europe. 
3. B. juncea Cosson. Similar to the preceding, but nearly or 
quite smooth. Pedicels slender, Beak slender, conical, not contain- 
ing a seed. Naturalized from Asia and becoming very abundant 
eastward. 
4. B. nigra Koch. Brack Mustarp. Stem 38-6 ft. high, some- 
what hairy. Lower leaves lyrate, with the terminal lobe much the 
longest; stem-leaves linear-lanceolate, entire or toothed, smooth. 
Pods awl-shaped, 4-angled, smooth, lying against the stem; seeds 
brownish, more biting than in No.1. Cultivated from Europe and 
introduced. 
VII. SISYMBRIUM L. 
Annual or biennial herbs. Radical leaves spreading ; stem 
leaves alternate, often eared at the base. Flowers in loose 
racemes, usually yellow, often bracted. Pods generally nar- 
rowly linear, cylindrical, or 4—6-angled ; seeds many, ellipsoid, 
not margined. 
1. S. officinale Scop., var. leiocarpum. Hepegre Musrarn. Stems 
branching, stiff. Leaves runcinate-toothed or lobed. Flowers very 
small, pale yellow. Pods somewhat 6-sided, awl-shaped, smooth, 
closely pressed against the stem. An unsightly weed in waste ground. 
Naturalized from Europe. 
2. S. canescens Nutt. Tansy Mustarp. Stem 1-2 ft. high. 
Leaves twice pinnately cut, usually covered with grayish down. 
Flowers very small, yellowish. Pods oblong, club-shaped, 4-angled, 
borne on pedicels projecting almost horizontally from the stem, in 
long racemes. Common westward. 
IX. RADICULA Hill. (RORIPA) 
Annual or biennial, mostly aquatic plants. Stems erect or 
diffuse, often widely branching. Leaves simple, pinnately 
lobed. Flowers small, white or yellow. Sepals spreading. 
