4) 
must have water, and, therefore it is that these plants require 
water in order to form their digestive secretions. 
Some of these insectivorous plants float upon the surface of 
the water, and so being in contact with the water, do not require, 
and so have not any roots at all. A good example of this kind is 
to be found in the common Bladderwort ( Utricularia) of our 
ponds and ditches. Others, not in immediate contact with water, 
but growing in marshy places, have very short roots, just sufficient 
to enable them to suck up water from the soil. The insectivorous 
plant best known to us is, perhaps, the Common Sun-dew of our 
bogs and moorlands ( Drosera rotundifolia ). This may be described 
as consisting of a saucer-shaped group of orbicular leaves, which 
are covered on the top by glandular hairs, each tipped with a clear 
transparent substance like a drop of dew, whence it derives its 
name. But this substance is in reality of an exceedingly viscid 
and tenacious nature, so much so that any fly alighting on the 
plant, and once touching this, is at once held fast, and unable to 
make its escape. At the same time the edges of the leaf which 
has been touched, begin slowly and gradually to curl upwards, 
until they meet at the top like the lid of a box. The leaf of the 
plant now becomes, to all intents and purposes, an improvised 
stomach, within which the operation of digestion is carried on. 
There is another plant of the same order which is still simpler 
it its arrangements, the Venus’s Fly-trap (Dionea muscipula ), 
found in North Carolina. This plant has not, like the Sun-dew, 
- any viscid secretion for catching and detaining the fly ; and, there- 
- fore, it would not do for it to close slowly, as in that case the fly 
t 
would have time to escape; it closes, therefore, sharply and 
instantaneously. Each leaf of the Dionea consists of two lobes 
hinged together at the end of a long foot-stalk, and armed at the 
edge with a series of strong sensitive bristles. Under ordinary 
conditions, the edges of the lobes remain wide apart, but the 
- moment an insect, or any other solid body in motion, touches the 
_ bristles, the marginal bristles instantly interlock like the teeth of a 
_ rat-trap, and shut the object in until the digestive secretions of the 
_ plant have had time to take effect. Each leaf of the Dionea is 
