DISCHIDIA WITH DOUBLE PITCHERS. 381 
the modified leaf. Treub’s figure (12) shows a median longi- 
tudinal section taken in a plane at right angles to that of 
fig. 11. Here the apex of the projecting lobe (ap.) is shown 
to be slightly incurved. The obvious inference is that the 
inner pitchers under consideration have been formed from the 
inflexed apical lobe, which in D. Rafflestana projects into the 
cavity of the pitcher, but has undergone no further complication. 
It would appear that the apex has become again inflexed by the 
growth and resulting curvature of the morphologically upper 
surface (seen en face in Pl. 9. fig. 11) between the apex and the 
“neck.” On this view the morphological apex of the leaf is 
represented in D. pectenoides by a small projecting tooth 
(tig. 4, ap.): in D. complex and in Haviland’s specimen it is 
situated in a similar position at the summit of the median 
groove (figs. 8, 6,7.) ; while in Motley’s specimen, owing to the 
further inflexion of the free margin, it is directed downwards 
into the cavity of the pitcher (fig. 10, ap.). It is of interest to 
enquire whether the inner or the outer pitcher was first formed. 
It has been shown, in the very young pitcher of D. Rafflesiana * 
(3 mm. long), that the growth was most active and the tissues 
showed least differentiation in the region immediately behind 
the apex. Ina more advanced pitcher (1 cm. long) growth at 
the base and apex had ceased, but was very active over the 
whole curved surface. And as at this stage the pitcher “ has 
attained its definite form,” it does not appear that apical growth 
is resumed. I therefore suggest that in these double-pitchered 
forms the involution of the apical portion of the leaf which gives 
rise to the inner pitcher takes place early in the formation of 
the organ, and precedes the general growth of the central 
portion of the leaf which produces the outer pitcher. 
Functions of the Pitchers. 
The functions of the pitcher as a whole, and of the inner 
pitcher in particular, remain to be discussed. At the outset, I 
am conscious of the danger and dissatisfaction of founding 
views as to function on such evidence as my material furnishes. 
At the same time, such indications as the pitchers examined 
do afford are of so striking a character that, in view of 
* Scott & Sargant, Ann. Bot. vii. pp. 208-4. 
