246 Bower . — On the Pitcher of Nepenthes : 
it by very broad bases ; there is, however, in Bauhinia no ex- 
tension of their growth across the adaxial surface. But if we 
pass on to stipules (which in many cases are without doubt 
essentially similar in their nature to pinnae, and may often be 
regarded as basal pinnae of peculiar character) similar de- 
velopments are to be found. In the intra-petiolar stipules 
(e. g. of Melianthus ) a coalescence of the two stipules across 
the adaxial surface of the phyllopodium has taken place, and 
such examples seem to approach most nearly to the constitu- 
tion of the lid as above suggested for Nepenthes . It is to be 
admitted that the emargination of the lid is often very slight, 
while in early stages of development the lid may appear to be 
actually entire (Figs. 11, 13) ; but in this I see no grave ground 
for doubt of the assumed congenital coalescence. Numerous 
examples might be cited of congenital coalescence quite as 
complete as this, where the fact of coalescence is beyond 
doubt— for instance in the stellate Ruhiaceae \ and especially 
in Rubia peregrina , all stages of coalescence of the stipules 
may be found, from those in which the two stipules of one pair 
are united at their base, through those united for half their 
length, to those which show only two terminal teeth, but have 
two prominent midribs, and finally to such as are absolutely 
entire at the apex, and have only a single well-marked midrib. 
In these last the coalescence (which on comparative grounds 
cannot be doubted) is complete and congenital, and in them 
we have an example closely similar to the cases shown in 
Figs. 11 and 13. In the mature lids of pitchers the venation 
may, as in the above-cited case of Rubia peregrina , show a 
certain relation to the external form, and on looking over a 
number of specimens in Kew, it has been seen that, as a rule, 
where the emargination is distinct the venation is referable to 
the two lobes ; while where the lid is most nearly entire there 
is frequently a single central rib more clearly marked than the 
rest. Similar observations may also be made on the coalescent 
pair of outer perianth-segments in Cypripedium . Other ex- 
amples might be cited, but sufficient has now been said to 
show that the lid of the pitcher of Nepenthes presents in its 
