1909.] STRAND PLANTS OF NEW JERSEY. 75 



effective in modifying the structure of the beach and dune plants, 

 but is hardly active upon the species of the thicket formation. 

 (7) Formerly it was supposed that the plants of the sea beaches 

 had to contend against the salt content of the soil, but Kearney has 

 shown that the amount of salt in the sand of sea beaches is a 

 negligible quantity, as many agricultural soils of the interior con- 

 tain relatively more salt than the seashore sand. 



While the beach plants have, therefore, according to the re- 

 searches of Kearney, been removed from the list of true halophytes, 

 nevertheless the typic salt marsh species show marked halophytic 

 adaptations and belong to the second category of strand plants. 

 The most potent factor which is here influential is the presence 

 of free salt water about the bases and roots of the salt marsh plants. 

 It was pointed out by Schimper that any considerable amount of 

 salt in the cell sap is detrimental to the plant and that here we have 

 the probable cause of the characteristic halophytic modifications 

 which aim, therefore, at decreasing the amount of water transpired. 

 To this Warming replied, that even if transpiration were diminished, 

 slowly, but surely, an amount of salt would accumulate in the plant 

 which would prove its destruction. On the other hand. Warming 

 proposed that the protective contrivances against strong transpira- 

 tion are necessary in halophytes, because absorption of water from 

 a salt solution is slow and difficult and what water the plant had 

 absorbed must be conserved in order to provide against desiccation, 

 while the plant is absorbing enough water to replace that lost in 

 ordinary transpiration. Sodium chloride in solution is known to 

 have strong plasmolytic properties, removing water from living 

 cells when subjected to its action. Ganong has found that the root 

 hairs of Salicornia herbacea, a typic halophyte, can endure a 100 

 per cent, sea water without plasmolysis; those of Sucuda maritima 

 80 per cent. ; those of Plantago maritima 70 per cent. ; while those 

 of Atriplex patulum withstood 50 per cent, sea water. Graves 

 found that the root hairs of Riippia maritima could stand a 105 

 per cent, sea water with occasionally very slight plasmolysis, while 

 with no per cent, sea water, it was rather slow, but finally distinct. 

 So that the group of halophytes with which we are here dealing 



