1909] 



OLSSON-SEFFER— VEGETATION ON SEA SHORES 



IOI 







Facies: Ammophila armaria, Elymus arenarius. 



Secondary: Triticum junceum, Car ex armaria, Festuca rubra armaria, 

 F. ovina, Poa pratensis, Cakile maHtima, Halianthus peploides. 



TABLE X 



Horn of 



READING 



Atmospheric 



temperature 



6 A. M 



7 

 8 



9 



io 



ii 



12 NOON 



I P. M 



2 



3 



4 



5 



6 



7 

 8 



9?6C 

 io.8 

 ii. 4 

 15.6 



23.2 

 26.3 

 27.2 

 27.0 

 26.4 



22.3 

 18.6 

 16.2 



Depth under surface 



2 cm. 



5 cm. 



10 cm. 



20 cm. 



50 cm. 



Cloud 1 



NESS 

 l-IO 



4.9 

 6-5 



7-7 

 9.0 



11 .2 



14.6 



17.2 



19.6 



19.4 



18. 1 



18.0 



*7-3 



12.9 

 11 .0 



4.2 



5-6 



6.9 



8.9 



10. 2 



11. 8 



I 3-° 



J 4-3 

 14.8 



14.6 



H. 3 



14.0 



13-5 

 12.3 



10.7 



5-7 



5-9 

 6.2 



6.9 



8.0 



9.6 



10.5 



11. 8 



12 .6 



12 .7 



12 .6 



11. 8 



11 .2 



10.4 



9-5 



9.1 



9-4 



9-4 

 9.6 



9-7 

 9.8 



10. 1 



10.7 



11. 4 

 11 .6 



11. 8 



11. 6 



11. 7 



11 .9 

 11. 6 



14 

 14 

 14 

 14 

 14 



14 

 14 

 14 

 14 

 14 

 14 

 14 

 14 

 14 



14 



3 



4 

 6 



6 



5 

 5 

 7 



4 



5 



5 



4 



5 

 6 



6 



7 



6 



3 



4 



3 



3 



5 

 4 



4 



5 



4 



2-5 

 1 



0.5 



The two species which constitute the facies of this community 

 usually occur in small separated patches, and measurements of the 

 temperature in the small sand elevations formed by these plants 

 revealed the fact that in the Ammophila patches the soil temperature 

 almost invariably was two-tenths to six-tenths of a degree higher that 

 »n the latter case, which would explain the lower temperature, but the 

 exact difference in moisture has not been ascertained. Many similar 

 '"stances of temperature differences have been noticed. Halianthus 

 Peploides always grows in colder places than Argentina anserina 



though both together often form a community. This question of 



temperature differences influencing the formation of communities, 



°*ever, needs further investigation before any decisive statements 



^ n be made. It must also be remembered that the temperature is 



Uenced b y the moisture, which in its turn depends to a great extent 



00 ?* P h y sic *l conditions of the soil. 



a ' Iecha nical analysis of sand.— A considerable number of such 



j^alyses have been made by the writer, and a few series will here be 



^ t0 show approximately the differences in size of sand grains on 



C Vanous formations on different sand strands. In the table the 









