200 THE OPEN BOOK OF NATURE 
woods. Let me tell you something about Fungi. 
What we call Mushrooms and Toadstools are really 
the fruits of Fungi that lie hidden beneath the 
soil. The Fungus plant consists of a number of 
small branching hairlike threads, built up of little 
cells. There are Fungi which can be studied only 
with the aid of the microscope. The Fungus threads 
are instrumental in breaking up decaying matter : 
they make their way through the substances in 
which they thrive and extract abundant food for 
themselves. They break up material—say, for 
instance, wood—rendering it soft and even pow- 
dery ; that is to say, they make wood rotten, so 
that it is easily reduced to dust or pulp, and can 
fall on to and increase the soil, forming vegetable 
mould. In this respect Fungi do Nature a service. 
But. they look after themselves in the progress of 
their work ; their main object in life seems to be 
to increase their kind ; and it is to secure this object 
that they send up fruits, like Mushrooms and Toad- 
stools. The gills of these fruits bear millions of 
tiny spores, which become scattered about and 
give rise to other Fungus plants like their parents. 
You know a Puff-ball ts a Fungus, and you have 
often burst them playfully when they were ripe in 
order to see the little cloud of dust which is made 
by the explosion. This dust is composed of myriads 
of Puff-ball spores. If you lay a Toadstool on a 
piece of paper and leave it for some time, on re- 
moving it you will find the paper is covered with 
spores which the fungus has shed while lying on it. 
Many species of Fungi are edible in addition to 
the ordinary Mushroom. Every year the Maned 
