70 THE HUMAN SIDE OF PLANTS 
attack living plants in multitudinous numbers, like 
wolves among sheep, or flocks of crows in a corn- 
field, leaving nothing but death and devastation be- 
hind. 
Of all the robber plants, perhaps the most inter- 
esting, certainly the most beautiful, is the tree- 
loving orchid, which belongs to a big family of 
plants known as epiphytes. In the truest sense of 
the word, they are not really robbers, because they 
seldom obtain their food from the tree on which 
they are found, but merely a “foothold”; their food 
comes from the air, through their own leaves. This 
great family of epiphytes is also represented by 
mosses and lichens and certain species of ferns; but 
its most striking member is the much-prized orchid. 
Of all nature’s subjects there is none so gorgeously 
apparelled. 
In the great tropical forests of South America 
the orchids cling in the tree-tops like small clouds 
of floating silks that at giddy heights have caught 
on to limbs of the tall trees. Their shapes and 
colours are weirdly fantastical: they imitate beetles, 
butterflies, moths, lizards, toads, scorpions, and 
sometimes even human faces! In colour nothing 
could be more extraordinary, nothing more fairy- 
like. Some dress in dark golds and browns; others 
unitate the spotted reds and blacks of huge poison- 
