PARASITIC ROOTS 165 



used in the propagation of some kinds of plants. For example, 

 Sweet Potatoes, which rarely produce seed, are propagated by- 

 means of the shoots which develop from the fleshy roots. The roots 

 are planted early in the spring in specially prepared beds, usually 

 hot beds, where they develop buds which grow into stems bear- 

 ing leaves and roots, as shown in Figure lU- These young plants 

 (slips) are broken loose from the potato and planted in the field 

 after all danger of frost is passed. The abundance of stored food 

 enables each potato to produce many sHps. 



Fig. 144. — Sprouting of the Sweet Potato. A, potato with sprouts in 

 different stages of development. B, sprout, or slip, broken loose from the 

 potato and ready to be set out. 



From the roots of the Red Raspberry ' and some Blackberries, 

 new stems called suckers grow up. These suckers with a small 

 portion of the parent root are used in starting new plantations. 

 The larger roots of the Raspberry and Blackberry are often dug 

 up in the fall, cut into pieces, and stored until spring when they 

 are planted in the field. From these root segments new plants 

 are produced. Roses are often propagated by root cuttings. 

 When plants can be propagated either by root cuttings or by 

 seed, it is generally better to use cuttings, because plants obtained 

 from cuttings usually grow faster and are more Kkely to be like the 

 parent plant than they are when grown from seed. 



' Raspberries. Farmers' Bulletin 213, U. S. Dept. Agr. Culture of Small 

 Fruits. Bulletin 106, Oregon Agr. Exp. Sta. Dewberry growing. Bulletin 

 136, Colorado Agr. Exp. Sta. 



