164 THE SAVANNAHS OF GUYANA, [Szss. Lxx. 
settles down during the cold nights in the dry season, where 
this dew is intercepted by the leaves of the trees in the 
forests, and but little reaches the soil. There are more 
factors worth considering: as I said before, the savannahs are 
inundated during a great part of the year, so that one can 
travel with great ease in a canoe from one place to another ; 
again, there is practically no month in the year without rain : 
the driest months, September and October, show a rainfall of 
50 mm. 
Before finishing this brief account, it is perhaps desirable 
to say a few words about another peculiar association, known 
in Dutch Guyana as Bieri-bieri. These Bieri-bieris are 
only found along the coast. They are of a pronounced 
xerophilous character, which is brought about by the large 
amount of salts contained in the soil; for all the land on 
which we find the Bieri-bieri is at or under sea level, and is 
therefore flooded by the sea or the rivers at high tide. They 
correspond nearest to the description of the savannah in 
lowlands, given by Schimper on pages 363 and 364, to which 
I referred before. But it is perhaps necessary to add to this 
description that the grasses are all covered with dense, stiff 
hairs and provided with sharp, cutting edges—the native 
indicates them by the general term of Baboonneffie, 2.e. 
Baboon knife—and further, that most of them are Graminez. 
Few other plants are scattered through these monotonous 
grass-plains. But now and then a small group of Avicennias 
or Rhizophoras, or Calladiwm arborescens and Drepano- 
carpus lunatus, show the places where shallow pools are 
formed in which now and then we may meet with one of 
the Lemnacee or Salviniaceze and stiff, leafless Juncacez. 
Putting all these data together, one might arrive at a 
conclusion in regard to the character and origin of the 
savannahs of Guyana. I wish only to show that the last 
word has still to be said; however, this communication may 
be a forerunner of what I hope to be able to say about the 
savannahs, and other points, after my views are enlarged 
by the guidance which I shall feel so happy to receive from 
the University of Edinburgh. 
