j0 q] OLSSON-SEFFER— VEGETATION ON SEA SHORES 109 



tions will, no doubt, give an explanation of certain hitherto unex- 

 plained features of the local distribution of strand plants. 



We often find on sandy sea shores a number of immigrants from 

 inland formations, and this occasional occurrence of plants which 

 do not naturally belong to such habitat shows that it cannot be the 

 chemical composition of the salt water that keeps so many island 

 plants from the sea shore, but other adverse conditions, which allow 

 only the peculiar sand-strand flora to develop. Even on the front 

 beach, where the salinity is greatest, w r e cannot attribute the scarce- 

 ness of the plants to the salt content, but to the easily movable sand 

 soil. 



As we have already mentioned, the lateral current of fresh water 

 flowing on the surface of the salty ground water near the sea has to be 

 aken into consideration when we discuss the salinity of the strand 

 soil. Our assumption that the conditions of the strand are not such 

 as to characterize this formation as halophytic is borne out by the 

 analyses made of the salinity of the soil at different depths. Many 

 true halophytes, of course, occur on the sea shore, but the strand 

 Hora as such must rather be classified as a halophile flora, while the 

 tme halophytes are those plants which are confined to saline situa- 

 tons m the interior, or where we know that the hydrodynamic condi- 

 tions do not change to any marked degree the salinity, as is the case on 



e S ^ a shore - If this holds good, the halophytes occurring on the 

 S Fa must be regarded as immigrants from dry saline habitats. 



everal Salsolaceous plants, widely spread in the interior of 

 t !!,lt la ' sometime s occur on the sea shores of that continent as 



but reach their best development in the dry 



™ o fwi specimens, 

 Sallne soil of the interior. 



on the 



maintains 



marsh ^ ^^ ^ a mUch less halo P hile flora than the san( ty or 

 ^trandV trandS * Th * S * S evident to everyone who has studied the 



many h ^ ** ShaU find that the plants even on the diffs exhiWt 

 fr °m theci aCterS ° f thC halo P h - ytes > and are sufficiently differentiated 

 as halo^-i Vegetation of inland situations to warrant a classification 

 bei ng i The P h y sical nature of the substratum prevents its 



*he dev i Pregnated witn common salt. We have here to account for 

 much ?f ment ° f ada Ptations so characteristic for halophytes, not 



rough the influence of salt in the soil as through the salt 



