266 HOW CHOPS GROW. 



represented in fig; 46, which infests so many farms. Each 

 node of the root-stock, being usually supplied with roots, 

 and having latent buds, is ready to become an independ- 

 ent growth the moment it is detached from its parent 

 plant. In this way quack-grass becomes especially troub- 



Fig. 46. 



lesomc to the farmer, for, within certain limits, the more 

 he harrows the fields where it has obtained a footing, the 

 more does it spread and multiply. 



Slickers. The rose, raspberry, and cherry, arc examples 

 of plants which send out subterranean branches, analogous 

 to the root-stock. These coming to the surface, become 

 aerial stems, and are then termed suckers. 



The Tubers of most agricultural plants are fleshy en- 

 largements of the extremities of subterranean stems. 

 Their eyes are the points where the buds exist, usually 

 three together, and where minute scales rudimentary 

 leaves may be observed. The common potato and arti- 

 choke are instances of tubers. Tubers serve excellently 

 for propagation. Each eye, or bud, may become a new 

 plant. From the quantity of starch, etc., accumulated in 

 them, they are of great importance as food. The number 

 of tubers produced by a potato-plant appears to be in- 

 creased by planting originally at a considerable depth, or 

 by " hilling up " earth around the base of the aerial stems 

 during the early stages of its growth. 



