A study in the Morphology of the Leaf. 241 
leaf is a simple, unbranched one, and the main question dis- 
cussed by them has been, which part corresponds to the petiole, 
and which to the lamina of ordinary leaves ? The chief views 
which have been advanced as. to the morphology of the pitcher 
of Nepenthes are the following : — 
(1) That the lid of the pitcher is the lamina of the leaf, while 
the rest of the leaf, including the pitcher itself, represents the 
petiole, which widens below into the broad assimilating expan- 
sion and basal sheath ; this is the view held by Van Tieghem 1 
and by Drude 2 . 
(2) Goebel 3 , on the other hand, holds that the lid of the 
pitcher does not represent the whole lamina, but that it is only 
the upper end of the lamina, of which the pitcher is also a 
part. He would imagine the pitcher of Nepenthes as essentially 
similar to the bladder of Utricularia , and says, ‘ If we imagine 
the bladders of the latter greatly enlarged, the lid not folded 
over the inner margin of the mouth, but closing the wide open- 
ing like a lid, we should have the pitcher of Nepenthes .’ He 
further regards the tendril as the result of intercalary growth 
from the upper limit of the petiole, the latter being represented 
by the broadly-winged basal portion of the leaf. 
(3) It is to be noted that both these views ignore the fact, 
long ago demonstrated by Sir J. D. Hooker 4 , that the apex of 
the lid is not the organic apex of the leaf, but that the latter is 
to be found in that spur which is constantly present in leaves 
of mature plants, immediately behind the point of insertion of 
the lid. Hooker, in the paper above cited, expresses the 
opinion that ‘ the pitchers are modifications of a gland situated 
at the apex of the midrib of the leaf’ ; he calls the lower 
flattened and winged part the lamina, and, speaking of the stalk 
of the pitcher, he says, c It is a body more or less strictly ana- 
logous to the terminal cirrhus of the leaf of Gloriosa or Flagel- 
lar ial He recognised what others who have written later 
failed to apprehend, that, f as the pitcher enlarges, the apex, 
1 Traite de botanique, p. 1462. 2 Schenk’s Handbuch der Botanik, i. p. 137. 
3 Ibid. iii. p. 238. 4 Linn. Trans, vol. xxii. 
