I 
THE EQUATORIAL FORESTS 
31 
brace it, if slender ; but when it has cHmbed up 
into the light it sends out stoutish free branches, 
clad with long sharp-pointed leaves of a uniform 
green, and the painted stem-leaves fall away. The 
common ivy is a familiar example of a somewhat 
similar mode of growth, coupled with dimorphous 
leaves. 
It was at Para that I first saw an enormously 
thick liana, sometimes near a foot in diameter, that 
wound in a regular spiral up the trees ; but often 
as I tried to trace its upward progress, I always 
found it intercepted at some height up by an 
epiphytal Clusia, beyond which I could not dis- 
tinguish it among lianas of various kinds that had 
accompanied it from the ground. It was not until 
I had been accustomed to see it occasionally for 
some years that I ascertained it to be really the 
descending axis of the said Clusia, several species 
of which possess that peculiarity, although the stem 
or ascending axis never twines, and the whole 
family of Clusiaceae or Guttifers has very few true 
lianas. 
Many lianas secrete abundance of fluid sap, 
usually milky and acrid in Apocynes and Asclepiads 
(which include a large proportion of all twining 
plants), turbid and virulently poisonous in some 
Paulliniae, but sometimes limpid, sweet, and harm- 
less. The Indians profess to know several lianas 
whose juice affords a copious and wholesome 
draught, but I could never trust myself to drink of 
any but the Dilleniacese, chiefly of the genus 
Doliocarpus. For this purpose it is not sufficient 
merely to sever the liana, when only a small 
quantity of fluid would gush out, but it must be 
