194 A NATURALIST IN BORNEO 



Clerodendron fistulosum is a shrubby herb about 

 5 feet high. It has a straight unbranched stem, woody 

 at the base, herbaceous at the summit. The lower 

 part of the stem is hollow. The internodes into 

 which the stem is divided are here short and rather 

 swollen. Exactly under the insertion of the leaves is 

 found a round hole, or two holes, with a prominent 

 thickened lip. As the leaves are opposite we should 

 expect to find two holes to each internode, one under 

 each leaf-insertion, but very often one of the holes is 

 absent, but is represented by a little circular patch of a 

 different texture and structure from the surrounding parts. 

 Occasionally there occurs an internode without any 

 holes at all. The cavity of one internode does not 

 communicate with the cavities of the internodes above 

 or below it, but every internode is separated from its 

 neighbours by a thick partition. An ant, Colobopsis 

 clerodendroniy has been found running in and out of 

 the holes. The singular fact about these holes is the 

 regularity of their position ; they occur under the leaf- 

 insertions always, whereas the holes in the stem of 



and the disappearance of the pith. In one class, the bud-bracts, 

 which cover the bud, bear some curious bladder-glands. The 

 bracts eventually become recurved into a ring-like chamber round 

 the stem, which contains " food-bodies " developed from the 

 bladder-glands. They are small white balls used as food by the 

 ants, which live in the hollowed stem or branch. In the other 

 class the bracts do not bear bladder-glands or food-bodies, but these 

 are borne on the under side of the young leaf, which remains for 

 some time with its lobes deflexed. To this class belongs Macaranga 

 caladifolia. These modifications are not due to any action of 

 the ants, as they occur whether ants are present or not, but are 

 of no advantage to the plant unless ants are present. Observa- 

 tions showed that when ants were absent the plant suffered 

 severely from the attacks of caterpillars. E. B. P. 



