Chapter V — 85 — Cephalotus 



collar, as will be clear in the figures. Correlated with size are the 

 simpler venation and small number of glands. Hamilton drew atten- 

 tion to this condition (1904). In the large pitchers the teeth are 

 concrescent with the rim and overhang it inwardly. Another feature 

 of juvenile pitchers is the large size of the lid, which is strongly arched 

 and widely overhangs the opening, so that it more efifectually pre- 

 vents the entrance of rain water, or appears to. As I have observed 

 these small pitchers are efficient in catching correspondingly small 

 insects. 



Transition forms between the large and small pitchers have not 

 been observed. When a relatively large pitcher appears after a number 

 of small ones have been produced, the passage from the small to the 

 large form is made at once in a jump. 



We turn to the anatomy of the pitcher {10 — 3, 6, 12). The 

 venation is derived from two systems of bundles in the petiole, a dorsal, 

 of three veins, and a ventral of two, these splitting near the pitcher 

 into four, then six and branching further in spreading. Referring to 

 the figures in which the veins are numbered, we see that of the ventral 

 system, Vi, (median ventral pair) passes into the lid, right and left 

 of the midline; V2 sends veins into the sides of the hd and into the 

 collar; V3 goes entirely to the upper part of the digestive cavity, 

 anastomosing with the dorsal veins. It seems quite doubtful that 

 Arber's statement about "the relatively high development of the 

 ventral system of the pitcher's venation" corresponds with the facts, 

 since one third of it is not connected with the lid at all, and only a 

 small part of it with the collar. Of the three dorsal veins of the 

 petiole, the median is the midvein of the pitcher, passing entirely 

 around it, and ending, not in the point of the median ridge, as Dickson 

 claimed, who therefore regarded it as the leaf apex, but in the collar, 

 opposite the middle tooth, there branching. Of the laterals (D2) each 

 runs obliquely down the side of the pitcher toward the upper end of 

 the glandular patch, having just before reaching it sent a branch into a 

 lateral ridge, whence it emerges in the collar. Traversing the glandular 

 patch obliquely it leaves it near the middle point and then runs up the 

 wall parallel to the midvein, and ending in the collar. The midvein 

 (Di) sends branches right and left into the lower part of the pitcher. 

 This basic arrangement of the vascular system of the pitcher can be 

 most clearly seen in a very young one, 3 mm. long {10 — 5). 



The external surface of the pitcher is covered with an epidermis of 

 isodiametric cells with thick walls, and is supplied with stomata and 

 nectar glands. On the lid the epidermis of the green patches is of 

 more or less wavy-walled cells, with glands and stomata interspersed, 

 while in the fenestrations the cells are isodiametric and straight walled, 

 with glands but no stomata. 



The epidermis of the interior surface of the lid and collar has been 

 already described above. That of the far interior is of wavy- walled 

 cells, the walls thick and buttressed at the angles. Scattered through- 

 out the surface, except along a narrow strip beneath the eave of the 

 collar, and the deeper portion of the pitcher demarked by an oblique 

 fine running downward and forward from about the middle point of 

 the back surface across the top of the glandular bolster, there are 



