418 DR. J. D. HOOKER ON THE ORIGIN AND DEVELOPMENT 
The examination of these remarkable seedling plants suggests the following obserya- 
tions :— 
1. The difference in the development of the leaf and pitcher in these seedling plants, 
and in the full-grown ones previously described, is very great, and at first sight anomalous. 
In the full-grown plant, the lamina, petiole, excurrent midrib, and pitcher are very inde- 
pendently differentiated, and the pitcher itself is first developed in the most rudimentary 
conceivable condition, that of a simple naked gland. In the seedling plant, on the other 
hand, the pitcher and lid appear to be developed in the earliest discernible condition of 
the leaf, which is that of a hollow midrib open at the apex and there closed with a lid, along 
each side of which midrib the lamina becomes developed in one plane (not with a convo- 
lute or involute vernation). As the plant grows, the upper part of the hollowed midrib 
of each succeeding leaf becomes more and more inflated, its apex protrudes beyond the 
lamina, as the neck of the pitcher, and the orifice and lid of the latter assume the usual 
highly organized condition of these parts in the genus. 
2. The position of the pitcher, occupying chiefly the underside of the leaf, is very 
remarkable, the appearance of the whole being not that of a pitcher with foliaceous 
margins, but of a leaf with a piteher partly adnate to its under surface; and tbe larger 
the leaf is, the more independent does the pitcher appear to be, and the more confined to 
the apex of the leaf; so that I expect that in more advanced states of the seedlings of 
this species, the pitcher will be found to be wholly free from the lamina of the leaf, 
though continuous at its base with the midrib *. When the plant arrives at such a stage _ 
of growth that the lamina of the leaf becomes a larger and more important organ than the 
pitcher, then the vernation of the leaf will assume the normal condition which obtains in 
the old plant. 
3. The horizontal development of the lamina on the sides of the pitcher, and the pro- 
longation of the margins of the lamina on the neck of the pitcher, at first sight seem 
to suggest the view that in the old plant the lamina of the leaf is represented by the 
wings of the pitcher, and that the apparent lamina is only a winged petiole. But in the 
seedlings the produced margins of the lamina do not reach the mouth of the pitcher; on 
the contrary, they converge, and form a transverse membranous wing below its orifice ; 
and the older the leaf is, the longer is the neck of the pitcher produced beyond this trans- 
verse lamina: and if the oldest of these seedling leaves be compared with that of a full- 
grown Nepenthes, it would appear possible that the transverse lamina is the true apex of 
the leaf, which in the old plant forms an elevated ridge on the anterior face of the base of 
the stalk of the pitcher+. This ridge, though generally small in most full-grown Jeaves, 
is often very prominent, so much so in N. Rajah (Tas. LXXIL) that the stalk of the 
pitcher is there peltately attached to the back of the leaf. , 
` Since the une observations were made, I have received from Messrs. Veitch more advanced seedlings, which 
ren this—the pitchers being wholly free from the lamina, but continuous at their base with the midrib. (October, 
se rette do not confirm this idea : it appears that the anterior wings of the old ye 
E: P ds of - lamina in the seedling pitcher, and that the transverse process uer 
üs ge an ors ^ the young pitchers is not developed in the youngest leaves of the seedling pps = 
need it occupies the whole space between the mouth of the pitcher and the transverse lamina. 
