BOTANICAL EVOLUTION, 413 
but whatever it is, insects go into these cups and become asphyxiated, 
though it is not very clear as yet how this is accomplished. At any 
rate, the bodies of numbers of insects are always to be found in the 
pitchers, undergoing a process of maceration, and there can be little 
doubt, judging from the analogy of other forms, that the plants absorb 
the nitrogenous materials formed by the decay of this animal matter. 
Another species, Sarracenia variolaris, has a much longer pitcher, and 
the leaf-blade forms a hood which completely excludes rain. Yet 
these pitchers, like the others, contain a watery liquid, which is 
evidently secreted by them. And further, the orifice and part of the 
inside of the pitchers have a sweet secretion formed on them, which 
lures flies, ants, and other insects to enter. The gas in the pitchers 
is apparently largely charged with carbonic acid, so that the unfor- 
tunate visitors which have once entered seldom or never escape; they 
fall to the bottom and are decomposed. Not only does this plant lure 
flying insects to its traps, but it provides a special bait for creeping 
ones, such as ants. The sugary secretion is developed not only on the 
lip and inner margin of the pitcher, but along the edge of the wing 
and right down to the ground, thus forming a pleasant path which 
leads unerringly into the very jaws of death. 
In the Asiatic and African pitcher plants of the genus Nepenthes, 
the pitcher is even more specially developed. From the figure it is 
evident that the leaf is remarkably differentiated ; the lowest portion 
acts as an ordinary leaf, the next portion has only the midrib 
developed, and this often forms a tendril by means of which the plant 
climbs; above this again is the pitcher, while the apical. portion—the 
true leaf-blade—forms avery perfect hinged lid. The pitcher is at 
first closed, but by the time the lid opens it contains a conside- 
rable amount of secreted watery fluid, while the orifice is provided 
with a sugary secretion to attract insects. When insects fall into 
the pitchers and are drowned the secretion of watery fluid is 
increased, the decaying animal matter appearing to excite the 
secreting glands, and Sir J. D. Hooker has shown that this fluid has 
distinct digestive powers. 
In the swampy ground in the neighbourhood of King George’s 
Sound, in Australia, occurs another very remarkable pitcher plant— 
Cephalotus follicularis—in which the same remarkable development of 
the leaf and its petiole has taken piace. Very little is known about 
this plant, but I mention it here to show how in three very diverse 
groups of plants, in three different parts of the world, the same 
singular modification has arisen. 
I remember very well, and I daresay some of you remember, the 
tales we used to read in our juvenile days of pitcher plants, which 
were a sort of special dispensation of providence for the use of thirsty 
travellers in arid climes. Unfortunately for the correctness of such 
stories all pitcher plants, no matter to what genus or species they 
belong or in what part of the world they occur, are only found in 
marshes or damp places. 
Down in the swamps of Stewart Island, I have on two different 
visits, gathered specimens of a bladder-wort, Utricularia monanthos. 
Here is a dried specimen, certainly a most minute, and, to most 
persons, a very uninteresting little plant. But all the species of the 
