362 
NOTES OF A BOTANIST 
CHAiP. 
tation in all these and in hundreds of other cases 
is invariably modified after the same fashion by the 
colour of the waters. How it became what it is, 
and how it came there at all, are questions not to 
be discussed here. 
After what has been said, it is scarcely necessary 
to add that many species of plants which grow down 
to the very coast in Guayana exist also in the 
Peruvian province of Maynas — that is, at the eastern 
foot of the Andes, and even up to a height of a few 
thousand feet in those mountains — e.g. Humboldt's 
Willow (Salix hu7nboldtiana, W.) and the Cannon- 
ball tree (Couroitpita guia7te7tsis, Aubl.), called 
Aia-uma or Dead Man's Head in Maynas ; while 
the proportion of Orinoco plants repeated on the 
Amazon is much greater than that of the plants of 
South Brazil. Nor does this uniformity of char- 
acter, and the constant recurrence of certain species, 
preclude the possibility of the flora being wonder- 
fully rich ; for I have calculated that by moving 
away a degree of either latitude or longitude I 
found about half the species different ; while in the 
numerous caatingas I have explored I always found 
a few species in each that I never saw again, even 
in other caatingas. 
The Relations of Plants and Animals 
The importance of inquiries of this class is 
obvious, even from a zoological point of view ; for 
that an animal should flourish in any region it must 
there find suitable food ; and there i^ perhaps no 
part of the world where so large a proportion of the 
animals is so directly vegetarian in its diet. I have 
