1904 | KEARNEY: PLANTS OF SEA BEACHES AND DUNES 435— 
tion of the soil solution in beach sands of the Atlantic coast of 
the United States must be at all times considerably less than on 
the California coast. This is further confirmed by the character 
of the vegetation, which is more decidedly halophytic on the 
California than on the Atlantic coast. 
This brings us to the question which serves as the title for 
this paper. In the light of the investigations just described, are 
we justified in classifying the vegetation of sea beaches and 
dunes as halophytic ?*4 
If the soil is not saline, or but slightly so, while ie climatic 
conditions are such as to render protection against excessive 
transpiration necessary, it is obvious that the vegetation, while 
xerophytic, is not halophytic. 
Ordinary cultivated soils of the eastern United States gen- 
eraily contain matter readily soluble in water to the amount of 
0.02 to 0.2 per cent. (by weight to dry weight of soil).5 Now 
n employing this term we do not lose sight of the fact that halophytes do not 
constitute an ecological class LPs with hydrophytes and xerophytes, but are 
properly only a subdivision of the latter. Like other xerophytes, they are character- 
ized chiefly by the possession of various adaptations for reducing transpiration, as 
Warming (Halofyt-Studie, p. 235) and Schimper tain cddahiscbaphid p- 99) have 
pointed out. Halophytes are such xerophytes as owe their — for a reduction 
of transpiration largely to the presence in the soil of an excessive amount of readily 
soluble salts. The character of the porl t is the final ces — decides saaitereed we 
shall call a given vegetation halophytic or non-halophytic. 
be cited as exclusively halophytic, diva alophytes seem to sini a more marked 
tendency than other xerophytes toward a development of water-storage parenchyma. 
phytic characters, as along the sea coast and in desert regions. The addition of a soil 
factor that makes absorption of water by the roots difficult (as is perhaps the case 
when salts are present in excessive amount) to climatic factors which tend to cause 
excessive transpiration from the leaves and stems should necessitate pions in 
the plant of every possible means for hoarding its water content. 
1§Data as to the amounts of salts in the soil solution endurable by various culti- 
vated plants not regarded as peculiarly resistant, are afforded by the very numerous 
examinations of cultivated soils that have been made by the Bureau of Soils in the ari 
western part of the United States. The bureau has found that snciey h when young, 
will endure 0.4 per cent., in later stages of oe 0.6 to 1.0 per ce t. of water- 
its fiber in the presence of 1.0 per cent. of salts in the surface 3°™ of the soil; and 
in Arizona in the presence of 0.9 per cent. in the first meter of soil. 
