I9I0.] 



ON THE DISTRIBUTION OF PLANTS. 



469 



withstand fresh water better than the fresh-water species can salt 

 water. These latter plants are able also to withstand an occasional 

 flooding, although normally they are controlled by fresh water. This 

 is probably to be accounted for by the resistance of the leaves that 

 surround the stem, while the roots are in practically fresh water, 

 which saturates the ground and prevents the entrance of salt water 

 into it for some time. The occasional flooding of salt water is not 

 for a sufficiently long time to efifect the character of the ground 

 water in which the roots of such plants as Sagittaria latifolia, Cicnta 

 maculata grow. 



The observations at Belmar began with an estimation of the 

 salinity of the ocean water. The readings from 4-19 are interesting 



Fig. 2. Basin-like slue along Fifth Avenue, Belmar, N. J., fringed by 

 salt marsh vegetation and backed by forest trees. Several of the stations 

 for hydrometric determinations were chosen along this shore. 



because they were made while Shark River Inlet was closed to the 

 sea by a sand bar. 



2. Sea water from surf at Belmar. Sp. gr. 1.0215 at 20.6° C. 

 (69° F.) ; corrected to 15° C. Sp. gr. = 1.0224. 



4. Water in Shark River Inlet flooding Spartina stricfa uiarit'una 

 association. Sp. gr. 1.015. 



5. Water from channel opposite B Street, Belmar. Sp. gr. 

 1.0185. 



