1895. ] Anatomical and Physiological Researches. 455 
The dunes and the schorres possess each a distinct type of 
vegetation. The plants of the former, owing to the extreme 
dryness which prevails, obtain water with great difficulty and 
furnish a series of structures adapted to secure proper absorp- 
tion and storage of the water taken from the soil, and a re- 
duction of the loss of water by evaporation. The wind, 
too, offers a very serious obstacle to the dune plants in their 
development. It lays bare their roots, enfilades the plants 
with sand, or buries them deeply in the drifts. 
Owing to unlike conditions of existence the schorre vege- 
tation is quite different. The earth isso compact that rain 
does not penetrate it; moreover, twice each day it is entirely 
inundated by the sea. Instead of resembling the flora of the 
apted to drouth. This is due to their xerophilous character. 
As is well known, vegetation becomes xerophilous not only in 
localities where water is rare, but also in places where, al- 
though sufficiently abundant, it occurs in sucha state as to 
be absorbed with difficulty. Thus the frequent and appar- 
ently astonishing xerophilous character of arctic and alpine 
plants which push into the water, is due to a large extent to 
the reduction of the amount of water which they can take 
from the soil, resulting from the simple cooling of the earth. 
n the case of vegetation in contact with the sea or an 
equally strong solution of salt, the plant absorbs water with 
difficulty since the liquid of the cells is much less concentra- 
ted than that of the external solution. Hence such plants 
need to economize their water so as not to be compelled to 
renew it frequently. 
2. Means of protection against drouth. The winters on 
the Belgian coast are humid and comparatively mild, while 
extreme drouth prevails during the summer. Hence many 
of the dune plants are exclusively bibernal in their growth, 
and, dried and shriveled, pass the summer in a dormant 
ate. 
The schorres, on the contrary, are almost completely de- 
prived of vegetation during the winter; the only plants which 
remain green are those with very short leaves (Glyceria, Ar- 
meria, etc.). This fact is probably due to the periodical sub- 
Mergence which the schorres undergo; the partly frozen 
water brought in by the tide tears up the soil and pulls out 
everything above its surface. 
