Bull. U. S. F. C. 1 901 . (To face page 80.) 
Plate 1 5. 
1. SAG ITT ARIA RIGIDA. 
The leaf in the center is from deep water; that at the right from shallow water near the shore. 
2. WINTER BUDS: POTAMOGETON ZOSTER/EFOLI US AT THE LEFT; P. PUSILLUS, UPPER RIGHT; 
P. FREISII, LOWER RIGHT, 
