152 



THE FACTORS 



[Part I 



readily be suspected. In Capura alata the large spoon-shaped stipules 

 of each leaf are bent in such a manner as to enclose within them 

 a chamber-like space, the marginal gap of which is closed as far as an 

 entrance-aperture by a kind of web spun by the ants. I found the 

 chambers nearly always inhabited by ants. Still more peculiar and 

 requiring morphological investigation was the state of matters in a tree, 

 described as Actinodaphne sp. coming from Salak, in which each twig 

 terminates in a roomy chamber lying above the minute terminal bud 

 and formed by a whorl of small scale-leaves. The phyllomes described 

 here as scale-leaves are distinguished from the foliage-leaves by much 

 smaller size, absence of petiole, and different shape. I have always 

 found the chambers inhabited by ants, which appeared to belong to 



a species very abundant else- 

 where in the garden. It is 

 no wonder that such suitable 

 structures should be inhabited 

 by ants ; it appears much 

 more remarkable that the hol- 

 low stems of Triplaris and 

 Humboldtia, provided with 

 entrance-apertures, should be 

 free from ants in the garden 

 of Buitenzorg, at least so far 

 as my observations go. 



Still further deviations from 

 the normal leaf-structure occur 

 among the tropical American 

 Melastomaceae in the genera 

 Tococa, Maieta, Calophysa, 

 Myrmidone, and Microphysa, 

 as well as, according to Schu- 

 mann, in the rubiaceous Remijia physophora and Duroia saccifera, and the 

 tropical African sterculiaceous Cola Marsupium x . Here at the base of 

 the blade of the leaf, on both sides of the midrib and sometimes also on 

 the petiole, are found two hollow outgrowths (Fig. cSq), which in the 

 Melastomaceae are situated on the under surface of the leaf and are to 

 be regarded as modified domatia, whilst in Duroia they belong to the 

 upper surface and morphologically represent new structures. 



All the above-mentioned plants, and others besides that are inhabited 

 by ants, are, as Schumann first pointed out, provided with an abundant 

 brownish-red coat of hairs, which appears in some way to be connected 

 with the symbiosis. 



1 See Schumann, I, regarding all these plants. 



Fig. 89. Tococa lancifolia. Base of leaf with 

 utricles. A seen from below, showing the entrance a. 

 B seen from above. Natural size. After K. Schumann. 



