The Fascinating World of Fungi
extraordinary organisms which are neither plants, nor animals.
one of the most important group of organisms on this planet
some of the world's largest and possibly oldest individuals
fairy rings, right out of children's story books
hallucinogenic magic mushrooms
some are silent killers with deadly poisons.
a vital ingredient in beer and bread.
decomposers, essential for natural recycling, helping to guarantee life on
miracle cures for disease.
indispensible partners for many plants.
Fungi are divided into three main phylums based on how related they are to each
other and shared reproductive habits. These phylums are: Basidiomycota,
Ascomycota, and Zygomycota. Basidiomycota are characterized by the presence of
basidia and dikaryotic fruiting bodies and include: mushrooms, puffballs, and shelf
fungi. Ascomycota are a diverse group and are characterized by the presence of
asci. They include: the cup fungi and mildews as well as the unicellular fungi, yeast.
Zygomycota are characterized by the presence of a thick-coated zygospore and
Types of Fungi
There are literally thousands of different kinds of fungi. Two hundred thousand species have
been identified world wide and there are likely to be well over a million species.
We identify different species mostly by the structure of their fruiting bodies and the
arrangement and types of spores which they produce.
There are a great many fungi which are very small (microfungi). They will not be
covered here. However, there are many other fungi with large enough fruiting bodies to be
There are over 3000 of these larger fungi in Britain.
Many fungi have fruiting bodies e.g. a mushroom which are stalked. This helps to raise the
spores some distance off the ground, so that when they are released, they can easily catch
wind currents and be carried to new places.
Fruiting bodies of fungi will generally produce millions of spores. A single fruiting body like
a mushroom, may produce more than 10,000 million spores!
Even though they are tiny, finding room for all these spores on a relatively small fruiting body
presents a major problem. The fruiting bodies of fungi are therefore cleverly engineered to
provide space for the production of enormous numbers of spores, without having to produce
an enormous fruiting body to accommodate them all. Different types of fungi have
accomplished this in different ways.
Fungi such as mushrooms, have
hundreds of paper-thin folds, called gills,
on the underside of the mushroom cap.
The spores are produced all over these
gills, which provide an enormous
surface area base for the spores. Gills
are sometimes also known as lamellae.
Some other fungi have small tubes or
pores within the fruiting body. The
spores develop all over the inside of the
pores, which again help to produce a
large surface area.
Still other fungi have developed fruiting bodies covered with enormous numbers of
tooth-like structures which bear the spores. Others just have large numbers of
folds all over the fruiting body. All of these different methods for increasing surface
area of the fruiting body and the different structures which result, provide a useful
way to identify different kinds of fungi.
How do fungi feed?
Fungi cannot make their food from sunlight, water and carbon dioxide as plants do, in the process
known as photosynthesis. This is because they lack the green pigment known as chlorophyll,
which plants use to capture light energy. So, like animals, they must obtain their food from other
organisms. They do this in three ways. They may break down or 'rot' dead plants and animals.
Organisms which obtain their food this way are known as 'saprophytes'. Alternatively they may
feed directly off living plants and animals as 'parasites'. A third group is associated with the roots
of plants in what are termed mycorrhizae.
Basidiomycetes and Ascomycetes
Fungi with sporophores (fruiting bodies) large enough to be readily visible will usually belong to one
of two main groups. The Basidiomycetes or the Ascomycetes. The main difference between these
two groups is in the way in which they produce their microscopic spores.
In the Basidiomycetes, the spores are produced externally, on the end of specialised cells called
In Ascomycetes, spores are produced internally, inside a sac called an ascus.
Asci and basidia are both microscopic structures.
Fungi with spores
Fungi with spores
produced inside a
sac called an
are 4 spores per
this varies from 1
depending on the
Each ascus usually
contains 8 spores
depending on the
For micrograph pictures of basidia and spores
Within the Basidiomycetes, there are three main groups. These are separated by means of
differences in the basidia and spores and how these are arranged on the fruiting body.
Gill Fungi (Order Agaricales and
Polypores, Chanterelles, Coral
Fungi, Crust Fungi, Fan Fungi
and Toothed Fungi (Order
Stinkhorns (Order Phallales)
Puffballs and Earthstars
(Order Lycoperdales and
Bird's Nest Fungi (Order
Jelly Fungi(Order Tremellales)
The basidia develop in layers,
called a hymenium, lining gills,
tubes, teeth or folds on the
Basidia are enclosed inside the Basidia in a hymenium or layer
on the outer surface of the
Asymmetrical spores, which are
shot off simple basidia.
Symmetrical spores, not shot
off the basidia.
The basidia are divided
internally - there are various