188 



CRUCIFERAE (MUSTARD FAMILY) 



Stems two to seven feet tall, or even 

 more in warm southern soil, branching 

 widely, sometimes hairy near the base 

 but usually smooth above. Lower leaves 

 pinnatifid, with the terminal lobe very 

 large and the several lateral lobes small, 

 toothed all around, with a long, slim 

 petiole ; upper leaves less divided, becom- 

 ing lance-shaped and nearly sessile at the 

 top. Flowers bright yellow, a little more 

 than a quarter-inch broad. This plant 

 is often confused with Charlock, or Wild 

 Mustard, but the difference between the 

 fruits readily distinguishes them : Char- 

 lock has long, knotted or wavy pods, with 

 stout, two-edged beaks, while Black Mus- 

 tard has short, smooth, four-angled pods, 

 a half -inch to an inch long, with short, 

 slim beaks ; and they are held closely 

 pressed to the stalk, making the raceme 

 veryslender. Seeds globular.almostblack, 

 very pungent to the taste. (Fig. 131.) 

 Means of control the same as for Charlock. 



SAND ROCKET 

 Diplotdxis muralis, DC. 



Introduced. Annual or biennial. Propagates by seeds. 



Time of bloom : June to August. 



Seed-time: July to September. 



Range : Nova Scotia to New Jersey and Pennsylvania, westward to 



Michigan. 

 Habitat: Fields and waste places. 



Not a common weed in this country as yet, but Professor Beal 

 reports that wherever found in Michigan, it " thrives and spreads at 

 an alarming pace." 



Stem one to two feet high, smooth or sparsely set with bristly 

 hairs, branching from the base, leafy only below. Leaves oblong to 



