380 MR. H. H. W. PEARSON ON SPECIES OF 
which represents one lobe of the pitcher seen from within, 
a portion of the near lobe seen in Pl. 9. fig. 9 having been 
removed. This pitcher also is thickly covered both outside and 
inside with small glandular hairs, and similar hairs are present 
also on the inner wall of the outer pitcher. 
Morphology. 
The material available furnishes very little direct evidence as 
to the morphology of these complicated structures. A com- 
parison with what is known about the pitcher of D. Rafflesiana 
affords, however, fairly clear indications of the probable course 
of events. The first modification of the type found in D. Raffle- 
siana is the flattened form of all these double pitchers, which 
suggests an organ formed by two leaves with their margins 
united. If, however, this view be entertained for a moment, it 18 
at once dispelled by an examination of the structure. The 
principal vein, obviously homologous with a midrib, traverses 
the margin of the outer pitcher from the petiole to the orifice, 
where it divides into two or more branches, though it is not clear 
that either of these enters the wall of the inner pitcher. The 
pitcher must therefore be regarded as a single leaf. The same 
observation disposes of Lindley’s suggestion (to account for the 
origin of the pitcher of D. Rafflesiana), that it is a leaf the 
margins of which are united *. Such evidence as there is, 
however, seems to support the now accepted explanation of the 
morphology of the pitcher of D. Rafflesiana which has already 
been outlined (p. 376), and we must suppose the double pitcher 
to be formed upon the same plan. In other words, the outer 
pitcber of these double-pitchered forms is part of a modified 
leaf, strongly reflexed on both sides from the midrib, whose apex 
and base, by the growth and consequent curvature of the inter- 
mediate portion, are closely approximated. In considering the 
origin of the inner pitcher, we must revert once more to 
D. Rafflesiana. 1 have copied two figures of the pitcher of that 
species, one (fig. 11) from Beccari t and the other (fig. 12) from 
Treub t. Fig. 11 shows the inside of the attached end of the 
pitcher. The apical lobe projects into the cavity of the pitcher. 
The apex of the inflexed lobe (ap.) is the morphologica! apex of 
* Lindley, ‘ Introduction to Botany,’ i. p. 302. 
+ Beccari, ‘ Malesia,’ vol. ii. Tav. 61. fig. 5. 
} Treub, Ann. Jard. Buit. iii. pl. 4. fig. 8. 
