THE SWEET POTATO. 77 



3. Purple spot at the base of the midrib. 



4. Veins all green. 



H. — Arrangement of Hair on Upper Surface of Leaf. 



1. Hair all over. 



2. Chiefly on tip and along veins. 



3. Absent. 



I. — Outside Color of Tubers. 



1. White. 



2. Yellow, golden or bronze. 



3. Yellow-red or pinkish. 



4. Red or i^urple. 



J. — Color of the Flesh of the Tubers. 



1. White. 



2. Cream-colored or yellowish-white. 



3. Pinkish-white or pinkish-yellow. 



4. Pink-orange. 



5. Marked with pnrx^le. 



K. — Distinctness of Wood Elements in Tuber. 



1. Distinct. 



2. Blurred. 



3. Not visible. 



In the determination of most varieties known to 

 the author there is no difficulty in referring all their 

 characteristics to the different alternative numbers 

 expressing them. In some varieties, however, it is 

 hard to tell whether the leaves reach a greater width 

 than four inches, as there are such few leaves that 

 do, and those might be exceptions. A similar diffi- 

 culty will sometimes present itself in other places. 

 All that is necessary is to express by the figures the 

 actual condition. Thus : A. 3-4 means that both long 



