THE FUNGI 163 
hyphee ramify over and through the nutrient 
substratum, and sometimes they cohere in 
strands. They then become easily visible to 
the naked eye and are popularly known as 
“spawn.” The spawn thus represents a 
specially luxuriant condition of the vegetative 
body or mycelium of the fungus, the mycelium 
being taken as a collective term for the mass 
of hyphal threads of which the vegetative part 
of the fungus is composed. Even the “ toad- 
stools ’’ and other fructifications of fungi are 
entirely produced by the organised weaving 
of the hyphe into more or less solid structures, 
followed by differentiation in the mass thus 
formed, together with the specialised growth 
of certain groups of hyphe. 
The fungus obtains the whole of its food 
from the substratum in which it is growing, 
and some of the nutriment is always of 
organic origin. Inasmuch as the fungus 
contains neither chlorophyll, nor any other 
material which would enable it to utilise 
the energy of sunlight, there is no necessity 
for the growing mass to expose itself to light 
at all. Indeed, to do so would carry with 
it the manifest disadvantages of removing it 
from the immediate source of nutrition, as 
well as of exposing it to the risk of desiccation. 
Now, having regard to the fact that the 
vegetative plant of the fungus is absorbing 
the whole of its food in a dissolved form from 
the material in which it is ramifying, it will 
be evident that the larger the surface, in 
