136 MORE ABOUT WEEDS 



prickles, grows from one foot to two feet in height, is 

 hollow, and gives out a milky juice when cut. The flow- 

 ers, which are produced in large heads at the top of the 

 stem, are bright yellow. The plant is perennial, and, like 

 the Canada thistle, grows from underground buds, as 

 well as by seed. In Figure 72, is shown a specimen of 

 the perennial sow thistle. Young plants of the sow 

 thistle, as they appear on the surface of the ground in 

 spring or autumn, are illustrated in Figure 73. 



FIG. 73. Young sow thistles. 



Sour Dock (called, also: Yellow dock, Curled dock, 

 Narrow dock, Curled rumex), Rumcx crispus. Like 

 the burdock, this plant is a coarse and homely intruder 

 into waste lands. Its roots are believed by some to be 

 valuable for use in medicine and its young leaves make 

 excellent greens ; but the ground it occupies is far prefer- 

 able to its company, and it should be persistently hunted 

 out and destroyed. 



The sour dock is a rank, coarse, deep-rooting perennial 

 weed. The rather slender branching stem grows to three 



