

1909] OLSSON-SEFFER— VEGETATION ON SEA SHORES 103 



a rule, sand is very deficient in plant food, and this is especially the 

 case with the commonest form of sand, that which consists mainly 

 of quartz. The quartz grains are insoluble, or only to a very small 

 degree soluble. Only in the case of lime or organic matter in the 

 form of humus entering into the composition of the sand is there 

 plant food in sufficient quantities to allow the development of a more 

 luxuriant vegetation. Generally the chemical composition of coastal 

 sands is very uniform, and this may to some extent account for the 

 evident similarity in vegetation on these formations. 



A number of analyses of sand have been made by the writer, and 

 ome typical results will be here related. 



No. 1.— Middle beach, Eckero Storby, Aland Islands, Baltic 



Per cent. 



Per cent. 



Insoluble matter 89.25 Alumina I -3 8 



Soluble silica 3 . 44 Water and organic matter 2.57 



Lime 1 .06 Nitrogen • • • °- l6 



Potash o. 18 Other constitutents i-Q* 



Phosphoric acid (soluble) 0.24 Total 100.01 



Peroxid of iron. 



0.71 



No. 2.— Littoral dune, Engelholmshamn, Skane, S.W. Sweden 



Per cent. 



Per cent. 



Insoluble matter 84.38 Alumina l8 3 



Soluble silica 

 Lime 



Potash 



4.53 Water and organic matter 4-93 



1 . 04 Nitrogen 



0.12 



o . 21 Other constitutents 2 °° 



Phosphoric ac id (soluble) 0.33 Total • • 99-99 



Peroxid of iron o62 



No. 3.— Upper beach, North beach, near Perth, W. Austr. 



Per cent. 



Insoluble 



Per cent. 



-»ume matter 86.32 Alumina O0 3 



?° 1Uble Sllica ... 3.61 Water and organic matter 2.89 



Lim_. . 

 Potash 



Phosph 

 p eroxid of iron 



[tone acid (soluble) Q .i 5 



1.53 Nitrogen • °'°3 



o . 36 Other constitutents 3 -33 



Total 



100.02 



O.87 



No. 4.— Duxes, Southport, Queensland 

 Insoluble Per cent PCr CeDt ' 



, matter 91-90 Alumina 



.08 



Ura e eSlUCa 3- lS Water and organic matter ... • 2.15 



Potash ° 86 Nitrogen °" 



o. 21 Other constitutents °-44 



^Phoric acid (soluble) 



**»* of ^.™ m) ° ^ Total IOOO ° 



