AQUATIC PLANTS IN POND CULTURE. 



11 



The water chestnut {Trapa natans), though fairly good as a food 

 producer and for shelter, shade, and ornament, is of negative value 

 in fish culture. 



E^G. 15. — Pickerel we«l (Pontederin cor- 

 data). Borders of ponds and streams, 

 Nova Scotia to Minnesota, south to 

 Florida and Texas. (After Britton 

 & Brown.) 



Fig. 16. — Greater duckweed (Spirodela 

 polyrhisa). Found in rivers, ponds, 

 pools, and siallow lakes. Nova Scotia 

 to British Columbia, south to South 

 Carolina, Texas, northern Mexico, 

 and Nevada. Widely distributed in 

 the Old World and tropical America. 

 (After Britton & Brown.) 



F^G. 17. — Lesser duckweed 

 {Lemna minor). Found 

 in ponds, lakes, and stag- 

 nant waters throughout 

 North America below 58° 

 N. lat. Also in Europe. 

 (.\fter Britton & Brown.) 



Fig. 18. — Water clover (MarnUen quadri- 

 folia). Found along the shores of 

 Bantam Lake. Litchfield County, Conn., 

 whence it has been introduced into 

 various parts of the country, notably 

 eastern Massachusetts. Native of Eu- 

 rope and .\sia. (After Britton & 

 Brown.) 



The lotus (Nelufnbo lutea) is troublesome to the pond culturist, 

 having bulbs extending 3 feet into the mud and being accordingly 

 difficult to remove when not desired. It is, however, very orna- 

 mental, good for shade, and fairly good for shelter. 



