250 Bower. — On the Pitcher of Nepenthes : 
difference between petiole and lamina. Further, if this be the 
case, there is no need to assume that their order of succession 
on the phyllopodium shall be always the same : it is quite 
possible to imagine the balance of intercalary growth charac- 
teristic of what we call the lamina to be localised near to the 
base of the phyllopodium, while the intercalation of a part, 
comparable as regards its development to the petiole, may 
take place higher up ; and this is exactly what takes place 
in Nepenthes , for the tendril-like prolongation is intercalated 
at the point marked ( x ) in Figs. 4 and 14. I would not go so 
far as to suggest the application of the term petiole to the 
tendril, and lamina to the expanded portion at the base, as 
this would be a use of established terms in a forced sense. It 
is, I think, preferable to drop the attempt to homologate the 
parts of all leaves to the usual plan as leading to unnatural 
comparisons, recognising, however, that the peculiar mode of 
development of the winged phyllopodium in Nepenthes shows 
in inverted order those characters which lead to the distinction 
of the parts usually termed petiole and lamina in ordinary 
leaves. It seems to me to throw no more light upon the mor- 
phology of the leaf of Nepenthes to call the basal expanded 
portion the petiole than it does to attempt to distinguish 
petiole and lamina in an absolutely sessile leaf : in other words, 
the terms petiole and lamina are to be used only in a descrip- 
tive sense, and it is not to be assumed that because such parts 
are commonly to be distinguished in leaves of complicated 
form, therefore the parts of all complicated leaves are referable 
to such a classification. In order to justify the use of the term 
petiole for the basal expansion of the leaf of Nepenthes it would 
be necessary to demonstrate that this plant was descended 
from a typically petiolate ancestor, and that the petiole had 
actually become transformed to the condition in which we see 
it ; but such evidence is not forthcoming at present. 
The above attempt to apply the method of treatment of the 
leaf, advocated in 1884, to a most problematical case has had 
the result of eliciting a new view of its morphology. The 
attempt has also shown that the method, which I believe to 
