the Szi'cct Potato. 



207 



to three-sixteenths of an inch in diameter, prostrate and root- 

 ing freely, green, with leaves arranged in two-fifths order. 

 Five to twenty such runners come from one root. The 

 longer vines, however, usually show more or less fasciation 

 at their tips ; they vary from a slightly oval cross-section to 

 great bands two or three inches wide and about an eighth of 

 an inch thick, bearing a dense head of leaves. Less commonly 

 the shorter branches are fasciated, and occasionally a flattened 

 sprout comes up in the propagating beds direct from the fleshy 

 root. As a rule, even the broadest fasciated stem will be 

 found round and normal near the parent root, and for three or 

 four feet therefrom. Then, tracing toward the tip, the stem 

 becomes oval and the phyllotaxy loses regularity ; these con- 

 ditions increase, one diameter remaining unchanged while the 

 diameter at right angles to it increases until the malformation 

 is fully developed, and the leaves are crowded together with- 

 out any trace of order. The internal structure of fasciated 

 stems is the same as in normal stems, modified only by the 

 shape of the cross-section. 



The frequency of fasciation in the sweet potato is shown 

 by the following table, giving the condition in five plants 

 taken at random : 



Number of 

 Branches. 



Length of Branch. 



Character of Branch. 



II. 

 III. 

 IV. 



V. 



2 

 I 

 I 

 I 



4 

 4 

 6 

 I 



S 



2 



17 

 2 



9 



9 feet. 



6 feet. 



6 feet. 



5 feet. 



6-12 inches. 



8 feet. 



Less than 8 feet. 



Normal. 



Fasciated and crumpled. 



Phyllotaxy irregular. 



Normal. 



Normal. 



Fasciated at tips. 



Normal. 



Fasciated. 



Normal. 



Fasciated. 



Normal. 



Fasciated. 



Normal. 



