CUTTINGS OF TUBERS. 59 



remain upon the portions, and these portions are then 

 treated in the same manner as independent mature plants 

 are, or sometimes, when the divisions are small and weak, 

 they may be handled for a time in a frame or forcing- 

 house in the same manner as ordinary cuttings. 



Cuttings proper may be divided into four general 

 classes, with respect to the part of the plant from which 

 they are made : i, of tubers; 2, of roots and rootstocks ; 

 3, of stems ; 4, of leaves. All these forms of cuttings 

 reproduce the given variety with the same degree of cer- 

 tainty that grafts or buds do. 



Tuber Cuttings. Tubers are thickened portions of 

 either roots or stems, and tuber cuttings, therefore, fall 

 logically under those divisions ; but they are so unlike 

 ordinary cuttings in form that a separate classification is 

 desirable. Tubers are stored with starch, which is de- 

 signed to support or supply the plant in time of need. 

 Tuber cuttings are, therefore, able to support themselves 

 for a time if they are placed in conditions suited to their 

 vegetation. Roots rarely arise from the tubers themselves, 

 but from the base of the young shoots which spring from 

 them. This fact is familiarly illustrated in the cuttings of 

 Irish and sweet potatoes. The young sprouts can be 

 removed and planted separately, and others will arise 

 from the tuber to take their places. This practice is em- 

 ployed sometimes with new or scarce varieties of the Irish 

 potato, and three or four crops of rooted sprouts can be 

 obtained from one tuber. The tuber is cut in two length- 

 wise, and is then laid in damp moss or loose earth with the 

 cut surface down, and as soon as the sprouts throw out 

 roots sufficient to maintain them they are severed and 

 potted off. Sweet potatoes are nearly always propagated 

 in this manner. 



In making tuber cuttings, at least one eye or bud is 

 left to each piece, if eyes are present ; but in root-tubers, 

 like the sweet potato, there are no buds, and it is only 

 necessary to leave upon each portion a piece of the epider- 



