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 incksum, 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. indsum, var. Harticegianum, 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 

 nearly erect on short, ascending pedicels, 

 making the racemes very slender. 



FIG. 137. Green 

 Tansy Mustard (Sisym- 

 brium incisum, var. fili- 

 pes). X I 



