A fungus is a cellular cryptogamous (flowerless) plant, nourished
through its spawn or mycelium in place of roots, living in air, and
propagated by spores.
Fungi--_mycetes_--are naturally subdivided into two great divisions:
1. SPORIFERA--those in which the spores or reproductive bodies are
_naked_ or soon exposed, as shown in illustration on page 79.
2. SPORIDIIFERA--in which the spores are _enveloped_ in sacs or _asci_.
These resemble in shape the _cystidium_ of illustration on page 79.
The first of these divisions--the SPORIFERA, or naked-spored fungi--is
again subdivided into four families, as follows:
1. _Hymenomycetes._ Hymenium, or spore-bearing surface, _exposed_
and conspicuous, as seen in the common mushroom and all Agarics and
Polyporei.
2. _Gasteromycetes_ (_gaster_, a belly). Hymenium, or spore-bearing
surface, _enclosed_ in a more or less spherical case, called the
peridium, which ruptures and expels the spores at maturity in the form
of dust, as in the puff-balls.
3. _Coniomycetes_, from the Greek κωνἱς, meaning dust, the entire
fungus having a _dust-like_ appearance. Mildew forms a good example of
this family.
4. _Hyphomycetes_, from the Greek ὑφα, meaning a thread. _Thread-like_
fungi, the filaments being more conspicuous than the spore masses, of
which group blue-mould affords an illustration.
[Illustration]
The Hymenomycetes (1) is again subdivided into six orders, the
discrimination being based on the diverse character of the spore
surface. The first of these orders is the _Agaricini_, or gill-bearing
fungi, to which our present chapter will be confined.