J. M. Macfarlane. — Nepenthaceae. 5 



The mouth of the seedling pitcher is bounded by a narrow corrugated rim, that is foraied 

 by outward and inward growth and reflection of the margin. The cellular and specially 

 the vascular tissue of the pitcher is prolonged round and behind the mouth to end in 

 a pointed process or spur on the dorsal side. This is the organic apex of the leaf. 

 Between the apex and the orifice the lid grows out to overhang the latter. The margins 

 of this lid like the margins of the lamina, are often glandular-ciliate. In the 8 th to 

 1 lh seedling leaf the pitcher is hollowed out of the midrib of the distal laminar half 

 only, and is being gradually constricted off round its base from the inferior or proximal 

 laminar half (Fig. \ E — F), which remains continuous with the winged petiole. The 

 laminar wings of the distal pitchered portion thus become the ventral wings of the 

 pitcher. These become wide and highly conspicuous objects in JV. ampullaria (Fig. 1 3, 

 p. 32), JV. Rafflesiana (basal pitchers), JV. bicalcarata and others. They are often 

 richly provided with alluring glands. In succeeding leaves the distal or pitchered part 

 becomes completely separated from the proximal part, that has usually been called the 

 lamina or blade, through increasing elongation of the midrib between the two (Fig. \ E) 

 and conversion of it into a functional tendril. It will thus be seen that the funda- 

 mental morphological similarity of the Nepenthes and Heliamphora (q. v.) leaves is 

 perfect, and that the rather puzzling adult leaf of Nepenthes is readily interpreted 

 when its morphological evolution from the earliest seedling stage is traced. 



The adult leaf in petiolate species like JV. phyllamphora, JV. Rafflesiana etc. 

 consists of [a] a petiole that is usually winged. The wings may be horizontal, or 

 directed obliquely or vertically upwards as in JV. rajah and JV. maxima. Frequently 

 the expanded base of the petiole and of its wings enlarge into an amplexicaul attach- 

 ment to the stem, while in such species as N. gracüis (Fig. 2) and JV. Burbidgei the 

 wings may be prolonged down the stem almost to the insertion of the next lower 

 leaf. That portion which we will subsequently speak of as (b) the lamina or blade 

 is clearly proved, by the above history of seedling leaves, as well as by leaf-embryo- 

 logy, to be but the basal part of the entire lamina. In view however of its relatively 

 extensive green surface, we will for convenience speak of it as the lamina. The pro- 

 longed petiolar midrib that is continued upward as the laminar midrib may be strongly 

 concave on its upper and still more strongly convex on its under surface. The lamina 

 varies from semimembranous to succulent-leathery or leathery in consistence, from 

 linear-lanceolate to oval or elliptic in outline, and from bright green to dark green or 

 reddish green in color. Rarely as in JV. madagascariensis the lower surface may be 

 greenish-crimson to crimson. In most species the laminar halves end abruptly or by 

 tapered extremities in the prolonged midrib or tendril. But in such as JV. rajah, JV. 

 Northiana and at times JV. maxima the halves of the lamina become peltately fused 

 above the excurrent tendril. The margin of the lamina is usually entire, but in the 

 group of related species that includes JV. phyllamphora and JV. Bernaysii the margin 

 is ciliate-toothed. 



Valuable characters for distinguishing the species are furnished by the venation. 

 In all of the species two or more veins run parallel to and on either side of the 

 midrib, but at varying distances from it and from each other. These usually start 

 from the midrib, near its junction with the petiole, but sometimes they pass directly 

 from the base of the petiole upward along its wings, and then spread into the lamina. 

 In a few species such as JV. alata, JV. madagascariensis and JV. Reinwardtiana each 

 leaf has sevcral pairs of veins, but the innermost two to four pairs spring at d afferent 

 levels from the rib, the innermost pair starting at or above the middle of the leaf, 

 while those further out start from the midrib at varying levels below. In striking 

 contrast to the foliage leaves are the bracts, which are typically sessile, and whose 

 venation nearly always differs fundamentally from that of the foliage leaves, even on 

 the same plant (Fig. \ 5). In these the longitudinal veins are undeveloped or appear 

 only as one or two faint marginal lines, while the substance of the bract is traversed 

 by an abundant reticulation of oblique or nearly transverse veins. The greatest 



