CUTTINGS AND GRAFTS 



377 



proper conditions of temperature and moisture. 

 These parts are cuttings (Figs. 399, 400). Nor is 

 it always necessary that the cuttings should be 

 made of stems. They are often made of roots 

 and frequently of leaves. Fig. 401 shows a plant 



Adventitious 

 plantlets on 

 begonia leaf. 



starting and roots forming 

 from the apex of a triangular 

 portion of a begonia leaf 

 which had been inserted in the soil. 

 When the farmer plants potatoes, he 

 makes cuttings of tubers. 



477. While many stems will grow when planted 

 bottom end up (as the willow often does), mak- 

 ing roots indifferently from either end, most root- 

 cuttings persist in making stems only from the 

 end which was uppermost on the plant. Fig. 402 

 is a picture, from life, of a root- cutting (0, N) 

 of horse-radish, which was planted bottom end up. 



