Groom . — On Dischidia rctfflesiana {Wall.). 225 
season, this plant is able only to live in the pockets, filled 
with moist humus, formed by the persistent leaf-sheaths of 
Palms. In regions not uniformly moist, the life of an epiphyte 
growing on a decaying tree will be endangered by the rapid 
evaporation of the water, and the speedy decomposition of 
the humus, on the surface of the host. D. rafflesiana is able 
to exist in spite of these dangers, because its stem and leaves 
possess a thick cuticle which is coated with wax : and, in 
addition, because its pitchers can store up water and nutritive 
material. Moreover, owing to the relative thinness of the 
leaf-canopy of its host, rain-water can pour directly into some 
of the pitchers. Whether or not D. rafflesiana actually 
requires a large amount of light, cannot be decided without 
further observation. But in its peculiar habitat on decaying 
trees — even when the bark is already peeling off — this plant 
escapes many epiphytic competitors which would struggle 
with it for food and light. 
For our knowledge of the plant we are mainly indebted to 
Wallich 1 , Griffiths 2 , Beccari 3 , and Treub 4 . Treub gives an 
account of previous observations and of the hypotheses 
advanced concerning the functions of the pitchers, as well as 
the results of his own careful investigations into the anatomy, 
development, and contents of the pitchers. He shows that, 
since the epidermis which lines the cavity of the pitcher is 
coated with wax, it is not adapted for the absorption of 
liquids 5 . Inside the pitchers he found living ants ; frequently 
water ; occasionally particles of detritus ; and rarely a dead 
insect or so. He concludes, ‘ En somme le role principal, si 
1 Wallich, PI. Asiat. Rar. vol. ii. 
2 Griffiths, loc. cit. 
8 Treub, Sur les urnes du Dischidia rafflesiana (Wall.). 
4 Beccari, loc. cit. 
5 It would be worth while to conduct experiments calculated to show to what 
extent liquids may be absorbed through the numerous stomata which are present 
in the epidermis lining the cavity of the pitcher. Each stoma, however, com- 
municates with the cavity of the pitcher by the agency of a relatively long narrow 
canal traversing the wax which is raised into a small turret above each stoma. 
Hence surface tension, and the presence of air in these canals, would greatly 
hinder, or wholly check, the absorption of liquids during the life of the pitcher. 
