118 DR. J. D. HOOKER ON THE ORIGIN AND DEVELOPMENT 



The examinatioii of these remarkable seedKng plants suggests the following observa- 

 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 fii'st sight anomalous. 

 In the fuU-gro'UTi 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 micbib 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 Ud 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 

 rcmai'kable, the appearance of the whole being not that of a pitcher with foliaceous 

 margins, but of a leaf with a pitcher partly adnate to its under surface ; and the 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 tliat in more advanced states of the seedhngs 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 I'epresented 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 i:)itcher f . This ridge, though generally small in most full-grown leaves, 

 is often very prominent, so miich so in N. Hajah (Tab. LXXII.) that the stalk of the 

 pitcher is there peltately attached to the back of the leaf. 



* Since the above observations were made, I have received from Messrs. Veitch more advanced seedlings, which 

 confirm this — the pitchers being wholly free from the lamina, but continuous at their base with the midrib. (October, 

 1859.) 



f These more advanced seedlings do not confirm this idea : it appears that the anterior wings of the old pitcher 

 do answer to the produced edges of the lamina in the seedling pitcher, and that the transverse process becomes 

 evanescent. The annulus of the young pitchers is not developed in the youngest leaves of the seedling plants, and in 

 the more advanced it occupies the whole space between the mouth of the pitcher and the transverse lamina. 



