/ 



THE NIGHTSHADE FAMILY 



91 



Let us Examine tlie tubers a little more closely. If we take two 

 potatoes of. equal size, peel one of them and expose them both 

 to the sun, we sjiall after some time notice that the one that was 



peeled begins to shrivel, where- 



as 

 ed. 



begins 



remains unchang- 

 The former has lost a great 

 deal of the water it con- 

 tained. If you plant it — 

 of course, with- 

 out removing 

 the buds, — no 

 plant 

 will 

 g r w 

 out of 

 it, for 

 the b u d s 

 are wither- 

 ed. So we 

 see that it 

 is the skin 



of the tiiber which protects it from withering. This skin, we are 

 told, consists of the same substance as cork. And we know 

 that cork is almost the best material available for preventing 

 the evaporation of liquids which are kept in bottles. Besides, 

 the coat of cork serves as a protection against any hurtful 

 influence from outside. Its bitter taste, for instance, saves the 

 tuber from attacks of insects. 



It is by means of these tubers that tlie Potato plant can endure 

 the hot and dry season. At the end of the season the plant is 

 full grown and has formed flowers, fruit, and seeds, as well as a 

 number of tubers under the ground attached to the mother plant 

 by string-Hke, horizontal runners or stolons (fig. 87, /?.). It will 

 now, for want of moisture in the soil, wither and die down to the 

 tubers which, protected under the ground, preserve the germ of 

 life in their buds. In the following year, when the soil gets 

 moist again, the buds begin to grow just as they do on any 



Fig. 87. — Formation of Potato-tubers. St. Stalk. Sc. Scaly 

 leaves, fi. Runners. T. Tubers. 



