Pitchered Insectivorous Plants. 
255 
Nepenthes the leaves produced immediately after the coty- 
ledons have the lamina gradually expanded from below up- 
wards, and towards the apex the margins of the laminar lobes 
curve round and fuse with each other in front of the pitcher 
(Plate XVII, Fig. 1). The tissue of the midrib in the upper half 
of the lamina opens out to form an elliptical and slightly 
bellied area on the dorsal 1 or upper leaf-surface view. This 
expanded dorsal midrib area is therefore bounded all round by 
the fused laminar lobes. The pitcher at this time appears as a 
ventral pouch-like cavity, adnate to the under surface of the 
lamina, and with its orifice projecting beyond the fused 
laminar lobes. A lid springs from the ventral side of the 
orifice, and from its junction with the pitcher a small fila- 
mentous process projects. This has been regarded by all 
writers on the subject as the organic leaf apex, and to this 
view I adhere. 
But to understand rightly the relation of parts in Nepenthes , 
as well as in the other genera to be treated of, we must ex- 
amine the vascular distribution. The vascular bundles of the 
midrib about the middle of the leaf begin to open out to 
form the framework of the pitcher. Two bundles, gradually 
diverging from each other on the dorsal side, run round and 
form the boundary of the bellied laminar area already men- 
tioned. Like the lamina these bundles, by forming anasto- 
mosing branches, fuse at the apex in front of the pitcher. 
As they run upwards they give off vascular branches, some 
of which spread out over the bellied area, and ultimately 
anastomose with each other along its middle. Other branches 
run into and traverse the laminar lobes, while the strongest of 
all are those spreading out along the lateral and ventro-lateral 
surface of the pitcher. The remaining bundles of the midrib 
run up the ventral part. The lateral and ventro-lateral 
branches of the two bundles, when they approach the orifice 
of the pitcher, curve round to the ventral side, and there unite 
with the ventral bundles to form the projecting filamentous 
1 Dorsal and ventral are used throughout in the sense of the leaf being a 
dorsi ventral structure. 
