—y 
DISCHIDIA WITH DOUBLE PITCHERS. 389 
state of our knowledge without becoming involved in unprofitable 
speculations. 
The genus Dischidia thus shows a series of leaf-modifications 
more remarkable perhaps than any other known genus of 
Phanerogamic plants. In D. Collyris and other species we find 
the root-sheltering concave shell-like leaf. D. Rafflesiana has 
assumed the distinct pitcher-form in which a higher degree of 
water-economy is reached, and the specialization is already 
so marked that the assistance of ants seems to be necessary 
in order that the roots may obtain an adequate supply of 
raw food-material. This species is the more interesting in 
that in cultivation it has produced a series of less specialized 
leaf-forms leading up to the normal pitcher*. The highest 
degree of specialization is attamed in these double-pitchered 
species, whose existence seems to be intimately connected with 
the residence of ant-colonies within the pitchers, and which have 
ccquired characters that appear to especially fit them to be the 
abodes of such colonies. Here the water-economy seems to have 
reached its highest point. But much of the story yet remains 
to be told. 
In conclusion, I desire to express my thanks to Sir William 
Thiselton-Dyer for kindly placing this material at my disposal : 
to Dr. D. Sharp and Colonel Bingham, who have allowed me to 
refer insects to them for determination ; to Mr. Massee, who 
gave me the benefit of his opinion respecting the mycelium 
represented in fig. 18, and made the drawing from which that 
figure was prepared; and to Miss Smith, to whom I am indebted 
for figs. 1-10. 
EXPLANATION OF PLATE 9. 
[All figures natural size, except 4, 10, and 13. Except in figs. 2, 3, 11, 
and 12, the pitchers are represented in the position they would occupy if 
growing upon erect branches. ] 
Figs. 1-4. D. pectenoides. 
Fig. 1. Leaf-bearing branch with pitcher attached. 
Fig. 2. A pitcher removed from the branch. 
Fig. 3. Pitcher shown in fig. 2, with portion of wall removed to show the 
inner pitcher. 
Fig. 4. Inner pitcher (enlarged). 
* Thiselton-Dyer, Ann. Bot. vol. xvi. p. 366. 
