12 



U. S. BUREAU OF FISHERIES. 



Had it been possible the waterweed, the water chestnut, the fennel- 

 leaved pondweed, the duckweeds, and the water clover would have 

 been eradicated. In ponds maintained for angling, however, rather 

 than for propagating purposes, these plants should not prove unde- 



FiG. 19. — Large yellow pond lily (Nym- 

 phwa advena). Found in ponds and 

 slow streams, New Bininswick and 

 Nova Scotia to Rocky Mountains, 

 south to Florida, Texas, and Utah. 

 Called also spatterdock. (After Brit- 

 ton & Brown.) 



Fig 20. — Long-leaved pondweed (Pota- 

 mogeton lonchites). Found in ponds 

 and slow sti-eams, New Brunswick to 

 Washington, south to Florida and 

 California. (After Britton & Brown.) 



Fig. 21. — Water chestnut (Trapa nor 

 tans). Naturalized in ponds, eastern 

 Massachusetts and near Schenectady, 

 N. Y. Native of Europe. (After 

 Britton & Brown.) 



Fig. 22. — Lotus (Nelumbo hitea). 

 Found locally in 0.ixtario and south- 

 ward to Florida, west to Michigan, 

 Indian Territory, and Louisiana. 

 (After Britton & Brown.) 



sirable except in depths of less than 4 feet ; though not without due 

 consideration of local conditions should the fennel-leaved pondweed 

 and the water clover be introduced, owing to their dense growth at 

 the surface even in deep water. 



