Bui. 1 95, U. S. Dept. of Agriculture 
Plate XV. 
Fig. 1.— Strong and Weak Tuber Units of the Gold Coin Variety of Potatoes. 
Nos. 1 and 2 represent strong and weak tuber units in 1911; Nos. 3 and 4 represent yields from 
tuber units 1 and 2; Nos. 5 and 6 represent yields in 1912 from five tuber units of Nos. 3 and 4. 
Fig. 2.— Strong and Weak Tuber Units of the Rural Blush Variety of 
Potatoes. 
No. 1 represents a strong tuber unit in 1911, with its 1911 yield and the 1912 yield from five 
of its tuber units. No. 2 represents a weak tuber unit in 1911, with its 1911 vield and the 
1912 yield from five of its tuber units. 
