424 Proceedings Portland Society Natural History 



Of more frequent occurrence are the incipient salt marsh- 

 es which are formed on muddy shores (Figure 50). These 

 are rarely of any great extent, consisting of scattered in- 

 dividuals or groups of such species as Suaeda maritima, 

 Glaux maritima var. obtusifolia, Limonium trichogonum 

 and Plantago decipiens, with larger patches of the Spar- 

 tinas, Juncus Gerardi or Carex maritima. These latter 

 may cover considerable territory by means of their creep- 

 ing rootstalks and furnish enough obstruction to the water 

 so that considerable silt is deposited about them. During 

 the winter, however, all traces of such embryonic marshes 

 are wiped out. They occur on the upper portion of the 

 lower beach, the lower portion being either bare or occu- 

 pied by eel grass and rockweed. The mud flats which are 

 found at the head of many of the bays (Figure 50) have a 

 vegetation consisting chiefly of Zostera, which is left strand- 

 ed at each receding tide, and various algae. 



c. Association-types of brackish marshes 



It is impossible to draw any sharp line between a salt 

 marsh and a brackish marsh for in many instances they are 

 continuous and support the same species, the differences in 

 salinity being too slight to effect the vegetation. In the 

 higher portions of the brackish marsh, however, several spe- 

 cies may occur which are not found in a typical salt marsh. 

 Among these may be mentioned : 



Hierochloe odorata var. Carex salina var. 



fragrans kattcgatensis 



Elymus virginicus Scirpus valid us 



Carex hormathodes Juncus pelocarpus 



Carex leptalea Aster novi-belgii 



The brackish marsh intergrades on its landward side with 

 fresh swamps and this transition area may contain species 

 of the brackish marsh side by side with such non-halophytic 

 plants as : 



