Structure of Fungi
main body of most fungi is made up of fine, branching, usually colourless threads called hyphae.
Each fungus will have vast numbers of these hyphae, all intertwining to make up a tangled
web called the mycelium.
The mycelium is
generally too fine to be seen by the naked eye, except where the hyphae are very closely
packed together. The picture on the left was taken through a microscope. The hyphae are
magnified 100 times life size.
||Some fungi, such as Honey
Fungus, which is a parasite of woodland trees, have hyphae collected together into
long cables, called rhizomorphs. Because there are so many hyphae packed
together, they are easily seen, forming black 'bootlaces'. These can
spread through a woodland infecting neighboring trees.
Fungal mycelium is mostly hidden from human view, not only because of its
small size, but also as a result of its location. The tangled mycelial mass is usually
hidden deep within its food sources, such as rotting matter in the soil, leaf litter,
rotting wood, or dead animals. The mycelium remains undetected until it develops one or
more fruiting bodies, containing the reproductive spores.
(such as mushrooms) are made up of thick collections of hyphae. They vary in size from
small and insignificant, to large eye-catching structures.
They are usually produced at the surface of the food source, rather than hidden within it,
to allow the spores to be shed and carried away by the wind, or by water, or animals. The
fruiting bodies are usually the only indication we have that a fungus is present. Like
icebergs, they represent a tiny fraction of the whole fungus, with most of it being hidden
If you are looking for fungi in Britain,
the best time to look is in the autumn. The fungal mycelia have then had a long,
relatively warm period to grow extensively over the summer. With the coming of
wetter weather in the autumn, damp warm conditions are created which are ideal for fungi
to fruit. Many fungi have fruiting seasons in late summer to autumn. However, don't ignore
the Spring. This is a good time to look for fungi such as Morels and other cup fungi. Little will be found in cold winter months
with frosts, although Oyster mushrooms will continue to grow through most of the winter,
as will Jew's Ear.
Fungal mycelia tend to
grow in more or less circular shapes. This is because they grow by spreading out
in all directions from a central point. This central point represents the location of the
original spore which germinated to start the fungal mycelium. The mycelium will usually
produce fruiting bodies on its outer edge. As a result, the fruiting bodies of fungi
living hidden in the soil can sometimes be found in rings - the 'fairy rings' of
|The Clouded Agaric toadstool (right) is a good example of this. The
fruiting bodies can often be found in rings, because they are produced on the outer
growing edge of the circular, underground mycelium. The Clouded Agaric can be found in the
leaf litter of both coniferous and deciduous woodland.
(image courtesy of
Another example is the 'Fairy Ring Toadstool' (Its scientific name
is Marasmius oreades). This, in contrast to the Clouded Agaric, grows on
grassy expanses such as lawns and golf courses. The fungus can be traced by the rings of
dark green grass, with the mushrooms fruiting on the outer edge of the ring. The growth of
the ring can be traced year on year. If there are no barriers, rings may grow outwards at
up to 20 cm per year. This is a fungus which
fruits early in the year, in the spring.
the natural world
Most people, if asked to name the largest organism
on earth, come up with examples such as elephants, blue whales or giant trees, such as
Redwoods. In fact, the largest living organism on this planet may well be a fungus!
In America, a single individual fungus,
similar to the Honey Fungus already mentioned, was found to cover a staggering
2,200 acres of land. (This is 45 times bigger than the Woodland Education Centre
in Offwell, for those of you who have visited the Centre before.)
Some of the oldest living
We tend to think of fungi as
being short-lived, because the visible fruiting bodies which we see don't usually
last very long. However, for the fungus to have reached this size, it must have been at
least 2,400 years old. It would have been a mere youngster of 400 years old, at the time
of Christ's birth.
The rings of Fairy Ring
Toadstools found closer to home in Britain, possibly on your back lawn, can also grow to
hundreds of meters in diameter, when they are likely to be at least a thousand years old.
which are a partnership between a fungus and an alga, have been estimated to be around
9000 years old!
Next time you find several fruiting
bodies of one type of fungus growing on the ground, see if you can follow around in a
circle and locate any more. The size of the circle will give you some indication of the
size of the mycelium hidden beneath your feet. Bear in mind when you do this, that the
fungus which is fruiting, will not be the only fungus hidden down there in the soil. In
fact the ground beneath your feet will be absolutely seething with the mycelia of
different fungi. We remain totally unaware of their presence simply because we can't see
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