398 PROCEEDINGS OF THE ACADEMY OF [Aug., 



observations may be made. Evidently, as it is exposed along the 

 channels which it fringes to the full effect of salt water (sp. gr. 1.0185), 

 the salt grass Spartina stricta maritima is the best adapted of all the 

 species studied to the halophytic conditions under which such plants 

 grow. Second in order of resistance to the detrimental influence 

 of saline solutions should be mentioned Spartina patens, Salicornia 

 herbacea, S. mucronata, Limonium carolinianum (sp. gr. 1.018), 13 

 Baccharis halimifolia, Distichlis spicata and Juncus Gerardi. While to 

 a third group of still less resistant halophytic plants, I would include 

 Typha angustijolia, Scirpus robustus, Gerardia purpurea, Solidago 

 sempervirens and Atriplex hastata. Such plants as Hibiscus moscheu- 

 tos, Cicutamaculata, Peltandra virginica, Panicum crus-galli and Sparga- 

 nium eurycarpum, mentioned in the foregoing account, are plants 

 indicative of fresh water marsh conditions, and are not to be included 

 among the true halophytes. 



Without experimental data, which I will later supply in a detailed 

 manner, with reference to the halophytism of all of the above-men- 

 tioned plants, the observations of Ganong 14 and Graves 15 have an im- 

 portant bearing upon our study of the distribution of the vegetation 

 of the salt marshes of northern New Jersey. Ganong has found that 

 the root hairs of Salicornia herbacea can endure a 100 per cent, sea 

 water without plasmolysis ; those of Suwda 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 Ruppia maritima could stand a 105 per cent, sea water with 

 occasionally very slight plasmolysis, while with 110 per cent, sea water 

 it was rather slow, but finally distinct. He also used solutions of 2.5, 

 3 and 5 per cent, sodium chloride with the following results. In the 

 2.5 per cent, solution, the leaves of Ruppia maritima did not plas- 

 molyze; in the 3 per cent, solution they plasmolyzed in 4-5 minutes; 

 in 5 per cent, solution in about 1 minute. Ordinary ocean water con- 

 tains about 3.5 per cent, of salts, and it would seem, therefore, on 

 a priori grounds, that the water of New Haven harbor does not contain 

 as much salts as the 3 per cent, quantity of sodium chloride in the 

 above experiment. It shows, however, that the adaptation of halo- 

 phytic plants is within a narrow limit of salinity, and if the salinity 



13 According to my hydrometer investigations, to be published later in detail, 

 the sp. gr. of sea water is 1.0215 at 21.1° C. 



14 Ganong, W. F. : The Vegetation of the Bay of Fundv Salt and Diked Marshes, 

 Botanical Gazette, XXXVI: 161-186, 280-302, 349-367, 429-455. 



15 Graves. Arthur H. The Morphology of Ruppia maritima, Transactions of 

 the Connecticut Academy of Arts and Sciences, XIV: 59-170, December, 1908. 



