PLANTS THAT ROB AND MURDER 61 
to form a kind of partnership with the host, where- 
by each is equally benefited. All such plants are 
degenerates and may justly be termed vampires. 
Robber plants have two ways of living: one 
kind, such as the dodder, thrives upon living plants; 
the other, such as puff-balls, mushrooms, and toad- 
stools, feeds upon a food material already prepared 
by other plants or by animals. The other form 
of parasite, like the mistletoe, which is partially 
honest, pays for some of its food; it may there- 
fore be politely classed as the “borrowing friend” 
rather than the “highway robber.” 
A striking example of a murderous parasite, 
or robber plant, is the dodder—or Devil’s-thread, 
as it is termed in many parts of Europe. Bot- 
anists refer to it as the Cuscuta. It has many 
relatives, among which even the respectable and 
honest-working cypress and morning-glory vines 
are numbered. Such a plant as the dodder has no 
green colouring-matter, chlorophyll, in its body, 
and it is therefore unable to secure food for itself, 
because it is by means of chlorophyll that plants 
are enabled to make food from the inorganic com- 
pounds furnished to them by nature. 
The dodder has no leaves, nor does it need any, 
as it gets all its food from the plant on which it 
grows; it has a few small scales that are possibly 
