Groom . — On Dischidia rafflesiana (Wall.). 235 
that they are feebly developed. But one might suggest that, 
as the development of roots in the pitchers of Dischidia is 
increased by increased supply of solid food, and as Treub’s 
observations on Myrmecodia were made mostly on plants 
deserted by the ants peculiar to the plant, possibly in normal 
plants there might have been more vigorous roots. It is highly 
probable that ants do bring substances into the galleries of 
Myrmecodia and Hydnophytufn , and it is extremely suggestive 
that within these galleries occupied by ants are lenticels 
through which water may be transpired and thus moisture be 
supplied to any solids present, and that there are also roots 
which can absorb any nutriment available. So in the pitchers 
of Dischidia rafflesiana there are stomata through which 
moisture may be supplied to the solids in the pitcher, and 
there are also roots by which the nutrient liquid may be 
absorbed. 
To sum up : 
(1) The pitchers are by no means mere water-reservoirs, 
though they often contain water which is of use to the plant. 
They are depositories for solids such as earth, humus, &c., 
from which, by means of the roots within the pitchers, the 
plant derives an essential portion of its nutriment. 
(2) The solids in the pitchers are partly derived from 
detritus washed down the stem and branches of the host-plant 
by the rain ; but they are also, and perhaps chiefly, brought 
by ants which nest in the pitchers. 
(3) The phylogeny of the pitchered leaf, traced through 
those species which have merely concave leaves, seems to 
indicate the evolution of an organ more perfectly adapted to 
provide shelter for the ants, on the one hand, and on the 
other to secure for the use of the plant the materials collected 
by the ants. Side by side with this main factor, the formation 
of pitchers conferred upon the plant the power of storing up 
rain-water and substances brought down w T ith it. 
II. The Structure of the Roots. 
Dischidia rafflesiana is by no means peculiar in possessing 
R 
