J. M. Macfarlane. — Nepenthaceae. 17 



up the white collar below the peristome that is characteristic of the species. The same 

 form of hair is developed in N. phyllamphora and related types. A second in N. 

 albo-marginata is the short thick-walled hair that bears one to three basal radiating 

 cells from whose united centre Springs a long strong 2 — 3-celled shaft, while a third 

 is the greatlj elongated multicellular hair that is most abundant along the midrib. 

 Each consists of 5 — 8 narrow thick-walled cells, the upper parts of which grow out 

 as lateral branch processes. This is the type that is specially abundant over the lamina 

 and outer pitcher surface of N. villosa, and which gives it specific designation. In 

 N. Veitchii five types of hair occur. In addition to sessile peltate hairs there are a few 

 thin-walled stellate hairs made up of 5 — 7 — usually 6 — long clear radiate cells. Many 

 short brown hairs, composed of a strong dagger-shaped central cell surrounded by 

 6 — 8 radiate basal cells (Fig. 6 B) give a fine brown pubescence to the leaves. Less 

 abundant are strong dark-brown greatly branched hairs that give a slightly hirsute 

 character to the lamina, and particularly to the midrib region of it. The fifth type is 

 that which gives the hirsute aspect to the unfolding, and even to the mature lamina. 

 It corresponds closely in histology to the long hair of N. villosa already described. 

 In studying the specific value of related species, and the probable parentage of doubtful 

 hybrids, the writer has found these hairs to be of extreme value, and they will 

 doubtless be regarded with increased interest in the future. Functionally the elongated 

 felted hairs evidently act as a protective covering to the young shoots and leaves against 

 over-rapid heat radiation and evaporation. But in the mature state of such species as 

 N. albo-marginata, N. Veitchii and N. villosa they possibly may act as felted moisture 

 holders for the general epidermal surface. 



The stomata (c) of the lamina are wholly restricted to the lower epidermis, 

 but are there very abundant. Their surface cell-area may amount to from y 3 to J / 4 

 that of the epidermal surface. Each Stoma is almost or quite circular in outline, and 

 the guard cells are well filled with chloroplasts. 



The epidermal glands (d) of the petiole and lamina vary in number and distribu- 

 tion in the different species. Each gland appears to the naked eye as a little greenish- 

 yellow papilla, with minute central orifice. Microscopically it differs from the stem gland 

 already described, in being flattened out in its glandulär tissue (Fig. 7 Ba). The glands 

 increase in number as a rule from stem and petiole up to the laminar end and the 

 tendril. Only a few species such as N. bicalcarata, N. Northiana and N. sanguinea 

 possess them on the upper surface, though 20 — 50 may be at times counted on the 

 two last. Their number, as compared with that over the outer pitcher surface, may 

 be indicated by the following statistics. In N. ampullaria three leaves showed 35, 

 50, 41 over the lower laminar surface, and 5, 7, 10 over the outer pitcher surface. 

 In N. Veitchii 70, 64, 81 were noted over the former, 115, 83, and 121 over the 

 latter. In N. khasiana one leaf showed 61 over the former and 260 over the latter. 

 As a rule the larger, more specialised, and more richly colored species, have a greater 

 number than the smaller less striking forms. That these alluring nectar glands should 

 wholly or mainly be confincd to the lower laminar surface is appropriate and ex- 

 plicable on principles of natural selection, when one remembers that insects in the 

 tropics usually run along that area, and so shelter themselves from the Observation 

 of enemies. 



The mesophyll tissue (e) may be divided into three zones, the aqueous, the 

 palisade and the spongy layers. The first consists of 1 — 3 strata of clear round — 

 or rarely (N. bicalcarata) transversely elongated — cells, placed beneath the upper epi- 

 dermis. In N. Veitchii this zone is about one-fourth the thickness of the entire lamina, 

 in N. Northiana about one-sixth, in N. bicalcarata it is one-eighth. The cell walls 

 show minute pore areas, and a few of the cells may contain crystals. The palisade 

 parenchyma consists of 2 — 5 layers of cells that may be slightly elongated vertically, 

 or rounded. or transversely widened [N. bicalcarata), and the cells are richly supplied 

 with chloroplasts. The loose parenchyma is twice to three times the depth of the 



A. Engler, Das Pflanzenreich. IV. (Embryophyta siphonogama) 111. 2 



