372 George E. Nichols, 



tion in the flood plain forests that have been developed on the 

 higher portions of flood plains, are well illustrated by the condi- 

 tions about the head of Margaree Harbor, which will be briefly 

 described. 



Pioneer association-types. — Owing to the intermittent backing 

 up of the outflowing river water by the inflowing tide water, 

 the depth of the water over the submerged portion of the flood 

 plain here fluctuates daily. On parts which are permanently 

 submerged, vegetation, where present, consists largely of sub- 

 mersed aquatics, notably Potamogeton bupleuroides. Areas 

 which are bared at low tide, but which may be inundated to a 

 depth of from perhaps six inches to two feet at high tide, are 

 occupied by a wet marsh association-type, in which the following 

 are the more prominent species : 



Equisetum fluviatile Acorus Calamus 



Scirpus occidentalis Castalia odorata 



Dulichium arundinaceum Nymphaea advena 



Typha latifolia Cicuta hulbifera 



Sagittaria latifolia Sium cicutaefolium 



Fringing the shoreward margin of this marshy area is a more 

 or less well defined transition zone, in which the predominant 

 plants are species of generally recognized amphibious proclivities. 

 Here, to a greater extent than in the areas of deeper water, 

 grow, among others, the following species : 



Leerzia oryzoides Proserpinaca palustris 



Juncus hrevicaudattis Lysimachia terrestris 



Iris versicolor Menyanthes trifoliolata 



C alt ha palustris Myosotis lax a 



Rumex Britannic a Mentha arvensis 

 Potentilla palustris 



On portions of the flood plain where the water at high tide 

 ordinarily is very shallow, or which are flooded only in time of 

 spring tides, the general aspect of the association-type is that 

 of wet meadow, although various of the marsh species may grow 

 here also. Below is a list of some of the species noted as 

 characteristic : 



