PLANTS THAT MIMIC 27 
plants, animals, and insects—or in some cases so 
subtly imitate the surrounding conditions as to 
pass unnoticed—in order to come under the pro- 
tection of those better equipped for defence. 
Every one knows that plants become changed ac- 
cording to their habitat. A tree from a tropical 
climate becomes a dwarf shrub in a northern 
climate; a desert plant often begins to drop its 
prickles when placed in a climate and under con- 
ditions where it no longer needs them; water-loving 
plants, like the mangrove tree, refuse to send out 
aerial roots when grown in inland places, and in 
some cases they actually change their form. There 
is no doubt that similarity of habitat produces a 
likeness in form. Water plants nearly invariably 
have long and feather-like leaves, which give the 
impression of floating or swaying in the water. 
A plant never mimics another plant or an insect 
without some good reason. Usually it is to deceive 
the enemies common to itself and to the better-de- 
fended plant that it pretends to be. Or if it as- 
sumes the shape and form of an insect, it is that 
flower-destroyers may pass it by. 
There are perhaps few examples of imitation in 
the plant world more wonderful than that found 
among the orchids. There is the bee orchid, with 
its marvellous labellum (lip or lower petal) of 
