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WATERCHESTNUT 



BOTANICAL 



Waterchestnut (Trapa natans), a native of Europe and western 

 Asia, was found in a lake near Scotia, New York, about 1884. 

 Since then it has spread to various points in New York State and 

 has become established in Massachusetts, Vermont, and Maryland. 

 Presumably it will continue to appear in new places. Other names 

 for the plant are water caltrop, waternut, bullnut, and shingoda. 



Waterchestnut grows in ponds, lakes, river estuaries, and slow- 

 moving streams at depths varying from a few inches to about 15 

 feet. It thrives particularly at depths of 2 to 5 feet and favors 

 muddy bottoms with high organic content. Though typically a 

 freshwater plant, waterchestnut tolerates slightly brackish condi- 

 tions such as those in parts of the tidal Potomac where the chlo- 

 rine content during the average growing season ranges from about 

 1,700 to 3,500 parts per million of water. 



Floating rosettes, commonly several of them produced on 

 branches of the same plant, top the flexible stems. Leaf stalks 

 are inflated, but not as conspicuously so as in waterhyacinth. In 

 early summer, small white flowers develop in the rosettes, and 

 these in turn produce large nutlike seeds armed with four sharp 

 spines having minute retrorse barbs. Most of the seeds germi- 

 nate in the following spring, but some may remain dormant and 

 viable for years. The empty seed shells float to the surface and 

 become a menace to bathing beaches. 



