194 CRUCIFERAE (MUSTARD FAMILY) 
stubbles for the purpose of killing the seeds on the ground. The 
plant gives no trouble in cultivated ground, for there the stroke of a 
hoe destroys it when young. The smooth foliage is unharmed by 
sprays. 
GREEN TANSY MUSTARD 
Sisymbrium incisum, Engelm. 
Var. filipes, Gray 
Native. Biennial. Propagates by seeds. 
Time of bloom: Late June to July. 
Seed-time: July to August. 
Range: Ontario and Manitoba, Minnesota and the Dakotas. 
Habitat: Grain fields and waste places. 
Root-leaves tufted, forming a graceful rosette, deeply pinnatifid, 
the segments again cut and toothed, peti- 
oled, deep green, slightly glandular, hairy. 
Stem leaves also all pinnatifid, but smaller, 
more finely divided, and with short peti- 
oles. Stem two to four feet tall, erect, 
branching, and finely hairy. Flowers bright 
yellow, about an eighth of an inch broad, in 
elongated racemes; pods smooth, narrow, 
slightly curved, a little more than a half- 
inch long, on slender, spreading pedicels. 
Seeds very small, reddish brown, minutely 
roughened, very mucilaginous when wet, 
which is an aid to their distribution. 
(Fig. 137.) 
Another nearly related plant with nearly 
the same range is the Gray Tansy Mustard 
(S. incisum, var. Hartwegiénum, Watson), 
differing in that its much divided foliage is 
densely covered with soft, gray, appressed 
hairs. The Gray Tansy Mustard is later in 
flowering and in seed development, the 
pods being but a quarter-inch long, held 
Fic. 137. — Green 
Tansy Mustard (Sisym- ‘ . 
brium incisum, var. fili- nearly erect on short, ascending pedicels, 
pes). Xt. making the racemes very slender. 
