



, 9 o9] 0LSS0N-SEFFER-VEGETATION ON SEA SHORES 91 



inland. Now it is not the absolute humidity that determines the 

 amount of evaporation, but the saturation deficit or the amount of 

 water which the atmosphere at a certain temperature is able to absorb 

 (Warming). In the continental interiors the evaporating power of 



summer 



sn 7). If we compare the 

 habits of certain plants which occur both in the interior deserts, and 



them 



Mesem 



same 



on the beach or in the immediate neighborhood thereof, as when occur- 



many 



the coast. But when found at a certain distance, o.5 km or so, from 



from the full force of 



fluence of the spray f 



from 



d its succulence is less marked than in specimens 

 .31 the interior. In the case of the writer's obser- 

 vation, the places of growth were as nearly similar as possible with 

 regard to exposure to the rays of the sun and moisture in the soil. 

 Some notable differences in anatomical characters observed in this 

 connection will be alluded to in another paper. These characters also 

 proved that the devices for protection against excessive transpira- 

 tion were not so well developed in the specimens which were not 

 exposed to the strong salt-laden winds, although they had the full 

 benefit of the coastal moisture. 



If we may be allowed to draw any inferences from this fact, we 

 should conclude that, as a rule, transpiration is less on coastal than on 

 ulterior s <Mds. There are other factors, however, to be taken into 

 consideration, which somewhat equalize the conditions, as the wind 

 and the salinity of the atmospheric moisture. 



Everywhere on warm coasts, especially in the neighborhood of the 

 Sea ' on the beach, we can notice a peculiar sand flora. It is charac- 

 terized by species which do not occur farther inland, and on the other 

 and inland Plants as a rule do not go down to the beach. The great- 



in salty situations. 



growing 



li *s generally assumed that the 

 nve are dependent on the amount 



As 



