475 
Ridley.—Symbiosis of Ants and Plants. 
tree which was half an inch and more in diameter and had developed 
a considerable amount of wood. In full-sized trees the ants still remain 
in the branches. 
It is quite rare to find a plant of this species not tenanted by ants, 
but I have found the shoots from a stool in an isolated position un¬ 
occupied, and occasionally a young plant also. This most usually occurs 
when a seedling has come up at a considerable distance from a parent 
tree, or from other plants which are inhabited by the ants. 
The bud-bracts. These are called stipules in the article in the New 
Phytologist and elsewhere, but, as above stated, I prefer to call them 
bud-bracts. 
They first appear as a pair of ovate triangular green bracts enclos¬ 
ing the bud. They have broad bases and an acute point, and often 
a low keel runs along the back. The under side at the base, as in the 
leaf, is thickly covered with bladder-glands. As the bud develops the 
bracts are reflexed, eventually coming into contact with the stem, and 
continuing to grow, become so elevated in the middle that the two form 
a hollow ring almost completely surrounding the stem. They are now hard 
and stiff, and usually of a dark purple colour, occasionally, however, retain¬ 
ing their green colour. On the under surface are innumerable glands, and 
thickly sprinkled over the surface are the food-bodies, very small, pure, 
white globular or elliptic bodies attached to the epidermis. Miss Smith, 
1 . c., describes them as golden yellow, but this I think must have been 
due to the drying of the specimens or the action of the preservative. 
I have always found them to be milky-white. The ants, which enter the 
hollow ring by the spaces between their outer corners and the stem, spend 
much of their time in this enclosed space and seem very unwilling to leave 
it. They often run about with the food-bodies in their mouths, and con¬ 
vey them to the hollow interior of the stem, where they supply them to 
the larvae. I have seen larvae actually underneath the bud-bract, evi¬ 
dently brought there by an ant, and lying on the abundant supply of 
food-bodies, but this is certainly unusual. 
Although the ants often remove many of the food-bodies to the nest, 
they do not clear them all away, though there are usually more to be 
seen in plants not occupied by ants than in those in which ants are 
abundant, and as the food-bodies are of different sizes, and apparently 
are in different stages of development, I conclude that they continue 
to develop and grow during the life of the bract. They are not to be 
seen on the bract before it has been reverted and has become appressed 
to the stem, and has thickened and turned red, when they appear in 
considerable numbers. They are rather hard externally, and when 
crushed exude a liquid which does not mix with glycerine and appears 
to be of an oily nature. The outer coat of the food-body is marked 
