THE ORIGIN AND VEGETATION OF SALT MARSH 



POOLS. 



(Plates IX-XIV.) 

 By JOHN W. HARSHBERGER, Ph.D. 



(Read April 14, igi6.) 



The natural, undisturbed surface of the salt marshes of our 

 eastern Atlantic coast is fairly uniform in character (Plate IX., Fig. 

 i) from Cape Cod south, as far as the mouth of Chesapeake Bay. 

 They are formed at the mouths of rivers, which empty into the ocean,, 

 and behind the barrier islands of sand, which fringe the coast, in 

 the quiet waters of the lagoons which become fringed with salt 

 marshes of varying width (Plate IX., Fig. 2), or the open lagoonsv 

 or bays, are completely invaded and converted into a salt marsh of 

 fairly large size. The tidal channels, or thoroughfares, as they are 

 called in New Jersey, still permit the entrance of sea water and the 

 surface of the marsh is partly, or wholly, flooded with water de- 

 pending upon the state of the tide. 



The outer margin of the salt marsh where it touches the open 

 lagoon (Plate IX., Fig. 2), or the tidal thoroughfare, is fringed with 

 a broader, or a narrower strip of the tall salt grass, Spartina glabra 

 (Plate X., Fig. i), depending upon the level and slope of the marsh 

 surface. Back of this strip, or association, we find the rush salt 

 grass, Spartina patens, which grows at a slightly higher tidal level,, 

 and is of varying width and outline, and then come the extensive 

 areas of the black grass, Jimcus Gerardi, upon which the economic 

 value of the marsh depends. Sometimes there are extensive areas 

 covered with the lesser salt grass, Distichlis spicata. The samphire, 

 Salicornia europcca, grows sometimes in pure association, sometimes 

 mingles with Spartina patens and Distichlis spicata, while the sea- 

 lavender, Limoniiim carolinianum, also grows in association with the 

 grasses and samphire in places over the surface of the marsh, as 

 also Snccda maritima and Atriplex pattda. Where fresh-water con- 



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