134 PLANTS WITH TRAPS AND PITFALLS TO ENSNARE ANIMALS. 



what appears to be the lid of the pitcher is the lamina, as it is in Cephalotus and 

 the Sarracenias. In this case also the lamina seems to be but little developed in 

 comparison with the wonderfully metamorphosed petiole. In the majority of the 

 species of Nepenthes, the mature pitchers are from 10 cm. to 15 cm. in height. In 

 the graceful Nepenthes ampuUaria they are only from 4 cm. to 6 cm. high; but, 

 on the other hand, in the species indigenous to the primeval forests of Borneo they 

 reach a height of 30 cm. or even more. The pitchers of Nepenthes Rajah have a 

 height of 50 cm., and their orifices are 10 cm. in diameter, whilst below the orifice 

 they expand to 16 cm.; so that if a pigeon were to fly into a pitcher of this kind 

 it would be completely hidden in it. Immature pitchers are still closed by their 

 covers. Often they are hairy outside; and, according to the colour and lustre of 

 the hairs, they may be rusty in tone or glittering like gold; not rarely they look as 

 if they were powdered with flour {e.g. N. albo-marginata), and sometimes are even 

 snow-white. Subsequently the lid is raised, and the downy coat disappears either 

 partially or entirely. Having thus become glabrous, the pitchers display a yellowish- 

 green ground colour, for the most part flecked and veined with purple; and many 

 are of a bluish, violet, or rose tint near the orifice, or dark-red as though saturated 

 with blood. The lid is similarly gaily coloured; and the variety of the tints is 

 increased by the fact that a pale-blue zone is visible in the interior, beneath the 

 swollen involute rim of the opening, which is itself brownish, yellowish, or orange- 

 red. Gaily-coloured pitchers of this kind look at a distance just like flowers, 

 and remind one, in particular, of the most brilliant floral forms of the liane-like 

 Aristolochias indigenous to tropical forests. This fact is the more noteworthy, 

 because the genus Nepenthes is closely allied to the genus Aristolochia in respect 

 of systematic relations. 



The bright pitchers of Nepenthes, visible from afar, are sought, just as flowers 

 are, by insects, and probably by other winged creatures as well; and this occurs all 

 the more because there is a copious secretion of honey by the epidermal cells upon 

 the under surface of the lid, and on the rim round the mouth of each pitcher. The 

 swollen and often delicately-fluted rim, in particular, drips and glitters with the 

 sugary juice; and it would be permissible in this connection to speak of a honeyed 

 mouth and sweet lips in the most literal sense of the words. Animals which suck 

 honey from the lips of Nepenthes pitchers wander, as they do so, only too readily 

 upon the interior surface of the orifice. But the inner face is smooth and precipitous, 

 and rendered so slippery by a bluish coating of wax that not a few of the alighted 

 guests slip down to the bottom of the pitcher and fall into the liquid there 

 collected. Many of them perish in a short time; others try to save themselves by 

 climbing up the internal face of the pitcher, but they always slip again on the 

 polished, wax-coated zone, and tumble back once more to the bottom. In large 

 pitchers the involute rim of the aperture is in addition armed with sharp 

 teeth, which are pointed downwards and bristle in front of such of the unlucky 

 victims in the pitfall as try to emerge (see fig. 19^). In a number of species 

 {N. Rafflesiana, N. echinostonia, N. Rajah, N. Udivardsiana, and N. Veitchii, all 



b 



