PLANTS. 81 



several pieces, but each piece must contain an eye. 

 Since the tubers grow and expand in the ground, 

 they require a loose soil for a good crop. 



Potatoes are planted in rows about four feet 

 apart so as to admit of cultivation; and the hills in 

 each row are from two to three feet apart. The 

 time for planting is from the final disappearance 

 of frost from the ground until July, according to the 

 variety. The early varieties mature, in central and 

 northern United States, about the first of July; 

 and the late varieties in September and October. 



The plant bears blossoms, and grows from two 

 to four feet high, with a tendency to vine, or run 

 along the ground; hence, the term potato vine. 

 As soon as the blossoming is fully over, all of the 

 nutritious substances of the upper part of the plant 

 are withdrawn and stored in the tubers, the vines 

 quickly withering till scarcely any trace of them 

 can be found a few weeks later. Corn or sun- 

 flower stalks have, so much substance left in them 

 that they exist a year or more after maturing; 

 but not so with the potato vine. What little 

 material is left in it soon decomposes and the 

 products return to the air and soil. 



Like all tubers and bulbs, potatoes are composed 

 largely of water, and must be kept in a temperature 

 above freezing, for freezing renders them unfit for 

 use as food. Corrj, and most seeds, contain such a 

 small percentage of water that freezing does not 

 affect them. Bulbs and tubers, however, can be 



