ARTICLES 



63 



The following table (I) shows the variation in the salinity 

 — estimated as chlorides — of the soil water taken from definite 

 stations at Erquy. The characteristic features of these 

 localities may be briefly mentioned. Station 1 is situated on 

 a low plateau which is covered by tides of about 37 ft. ; station 

 6 is a pan, the soil of which is argillaceous and does not support 

 vegetation, which is covered by tides of over 39 ft. ; and 

 station 18 is a patch of sand inundated by tides higher than 

 33 ft. It must also be remarked that the salinity of the sea- 

 water at Erquy is about 3*15 per cent., estimated as chlorides. 



Table I 



A consideration of these figures shows that the roots of salt- 

 marsh plants may be subjected to considerable variations in 

 the salt-content of the soil. 



These variations in the external conditions of growth 

 obtain not only for salt-marsh plants like Salicornia, but also 

 for others. Osterhout 1 has described how marine Algae 

 attached to the sides of coasting steamboats may be subjected 

 to very considerable variations in the salinity of the water, 

 the daily range being from highly concentrated sea-water on 

 the one hand to fresh water on the other. He also found that 

 delicate marine Algee taken from the sea could grow for 

 months in fresh water ; further, that Algae taken from normal 

 sea-water and placed in concentrated sea-water flourished for 

 one or two months ; and finally, that similar plants taken from 

 the sea lived for long periods in diluted sea-water. 



1 Osterhout, Univ. Calif. Publications, 2, No. 8, 1906 ; No. 9, 1906. 



