66 



AGRICULTURE. 



eyes are buds ; so that 

 what we plant are cut- 

 tings of the underground 

 stems of the p'lants. 

 Observe the arrange- 

 ment of the eyes in the 

 potato. Rightly, then, 

 we speak of the potatoes 

 as being tubers not roots. 

 Jerusalem artichokes 

 also are tubers. 9 



If you cut open a 

 potato you find it filled 

 with a starchy substance 

 generally white in color. 



Fig. 27. Potato plant, showing B the true roots ; If yOU CUt Up fine a SUgar 



C, the underground stems; A, the tubers, which . _. , 



are swollen or enlarged parts of the stems. The DCet anu place It in a 



eyes in the potato tubers, therefore, are buds. 



coarse towel you can 



wring the juice out of it quite easily, you cannot easily do so 

 with potatoes. You conclude that potatoes have less water 

 and more dry matter or food in them than have the roots. 

 If you evaporate the juice from potatoes you find littfe or no 

 sugar. Then we conclude that roots have large quantities of 

 sugar and water in their make-up, but potatoes have less water 

 and quite a large amount of starch. 



The potato, the tomato, and tobacco belong to the family 

 known as Solanacecz. The sweet potato is the root of a plant 

 grown in very warm climates, and belongs to the family Con- 

 volvulacecR) as do the morning glory and dodder. 



New varieties of potatoes may be got by sowing the seed 

 and selecting the best tubers so grown, planting these and 

 selecting the best grown from them, and so continuing. 



