192 



Whenever these variations tend towards greater productiveness, 

 l)etter quality or enhanced beauty, selection is again made of such 

 specimens as give promise of supplying the wants and gratifying 

 the desires of civilized man. The bettered conditions of the plant, 

 by reason of man's effort, do not usually result in piK)ducing like 

 variation along all lines. One part of the plant as the flower, the 

 fruit oi" the stem, varies more than the other parts. xVU tliis tends 

 to break up a single type or stock into many varieties. There are 

 linndreds of varieties of potatoes all traceable to a single wild 

 species. The Kind and (piantity of nourishment supplied plays the 

 most important part of any single factor in producing variation. 



The general character of the cultivated potato plant as to leaf, 

 stem, root and habit of growth, is virtuallv the same as the wild 

 plant, variation having been directed and accentuated along the line 

 of increasing the size and quality of the underground tubers. This 

 habit of producing enoi'mously enlarged stems has been operating 

 so long that the plant has inherited the power of transmitting this 

 acquired quality to the succeeding plants. The most improved 

 varieties seldom produce seed balls because growth has been directed 

 so largely toward enlarging and multiplying the tubers. By select- 

 ing tubers with buds not fully developed and avoiding those with 

 deep, sunken ey£s, varieties have been produced with few eyes or 

 buds and these set not in deep indentations but nearly even with the 

 surface of the potato. 



jrw 





'M. 



11.'"'%'/ 



292 



