8 



are two small leaves, forming as it were a bud. These 

 leaves are very close together, placed in a very similar 

 manner to two hands laid palms together lengthwise. 

 Instead of these leaves parting and spreading out in 

 opposite directions they are brought into closer con- 

 tact, as starchy matter, developed in the leaves on the 

 above-ground branches, is gradually carried down the 

 stems and deposited between them. The greater part 

 of the starchy matter not required to support the plant 

 is conveyed to the underground stems, and accumu- 

 lates between these small leaves. In a short time the 

 leaves become distended, but they are equal to the 

 occasion, for as the starchy granules become attached to 

 them they lose their leaf-like properties and develop 

 into skin. The tubers increase in size, but the skin 

 develops rapidly enough to form a covering to them, 

 and in course of time the tuber, as it is commonly called, 

 comes to maturity. In the tuber a number of buds, 

 commonly known as eyes, are formed, and these lie 

 dormant until various changes within, and favourable 

 conditions without, start them into growth. The con- 

 tents of the tuber then become food for their support 

 until the roots develop, and the young plant can take 

 nourishment from the soil. The tuber is therefore 

 the distension of a leaf-bud at the end of an under- 

 ground stem, the distension being caused by an ac- 

 cumulation of starchy matter manufactured in the 

 leaves, and brought there to be stored as a reservoir 

 of food to support the life of the buds when they start 

 to grow, and until they have developed into plants 



