76 THE SWEET POTATO. 



requires somewhat more work for the determination 

 of some varieties. The reasons will be given later. 



A. — Shape of Leaf. 



1. Cut. 



2. Eound. 



3. Long. 



4. Broad. 



5. Mixed (round and lobed). 



B. — Size of Leaf. 



1. Small (less than four inches across). 



2. Large (more than four inches across). 



C. — Length of Stem. 



1. Long (more than four feet long). 



2. Short (less than four feet long). 



D. — Color of Stem. 



1. Green (with or without brownish areas). 



2. Green, with purple around the axils of the 

 leaves. 



3. Greenish-brown to purple. 



4. Purple. 



E. — Size of Stem. 



1. Thin (less than ^/,s inch in diameter). 



2. Thick (more than i/g inch in diameter, often 



t\ or more). 



F. — Presence of Star. 



1. Star present. 



2. Star absent. 



G. — Color of Lower Surface of Veins. 



1. Veins purple. 



2. Midrib pinkish in some old leaves. 



