MODIFIED STEMS 



183 



STOLONS OF WHITE CLOVER. 

 A leaf appears at each node. 



c, Rootstocks are also underground stems. Many grasses 



produce branches that 



burrow into the ground. 



These branches show 



regularly arranged 



nodes and internodes. 



The leaves of these 



underground branches 



have been reduced to 



whitish scales or have 



entirely disappeared. 



Many plants keep alive 



through the winter 



through their rootstocks. The part of the plant above 



the ground is killed; but the underground stem remains 



alive because of the 

 protection afforded by 

 the ground. In the 

 spring, a shoot, or new 

 plant, may be sent up 

 from any of the nodes. 

 This is why the farmer 

 may have a permanent 

 pasture without replant- 

 ing, and why he is 

 troubled by quack grass 

 and Canada thistles. 



d. Stolons are creep- 

 ing steins, like those of 

 the strawberry, dew- 

 berry, and currant. 

 After creeping on the 

 ground for a few inches 



or a few feet, a stolon bends over, strikes root at the tip, 



STRAWBERRY RUNNERS. 



Four runners have started from the 



plant at the top. 



