265 HOW CROPS GIJOW, 



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 



lesome 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, are examples 

 of plants which send out subterranean branches, analogous 

 to tho root-stock. These coining to the surface, become 

 aerial stems, and are then termed snckerx. 



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 

 r=r propagation. Kadi eye, or Imd, may become a new 

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

 lhe:n, they arc 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 &quot;hilling up&quot; earth around the Lase of the aerial stemV, 

 during tl&quot; early stages of its growth. 



