December 2019 BBC Wildlife 21WILD DECEMBER
ungus where and when it is
eeded. When conditions dry
the horizontal growth, like
outer surface, forms a dense,
xy layer, further protecting the
ungus from dehydration.
The point of this stroma and
hereason the fungi breaks
er like it does is all about the
duction of spores, of which
re are two kinds. The first are
ifficult to see and are produced
while the fungus is in its pinkish,
ubbery growth phase. These are
asexual spores. Once the stroma
ripe and blackened, they
duce sexual spores.
Look at the surface through a
nd lens and you’ll see a
ndscape that looks like the
texture of ostrich skin leather.
Each bump is the swollen
trance to a flask-shaped pore,
perithecium. The inner
rface of this ruptures and, by a
rocess of unequal water
ressure, fires up the black
pores. Place your specimen
n a white sheet and overnight
ou’ll see that a halo of black dust
to 3cm away appears all
ound it. Each is a microscopic
ture Daldinia, fired out into the
oodland world. Often the wood
urrounding a ripe stroma will
besimilarly stained by the
ejectedspores.Iustrat
ons
by
Peter
Dav
dScott/The
Art
Agency
NICK BAKER
s a naturalist, author and TV presenter.Revealsafascinating
worldofwildlifethat
weo enoverlook.The distinctive
black fungus domes
ten erupt on fallen
h trees.Cutdown through one and
youwillsee the formation that
givesriseto the second part of
theirscientific name, concentrica
(thefirstpart, Daldinia, comes
fromthemycologist monk
AgostinoDaldini): a beautiful
arrangement of alternating
concentricrings of silver and
black.Thepattern is reminiscent
oftheannual growth rings
foundintrees. Here, though,
thewholestroma is produced
inaround a year and each
hasin the region of 20
zones. Each zone
corresponds to times
when conditions were
moist and favourable
for fast growth.Dry survivor
When those conditions
are right, the tube-like hyphae
grow outwards from the centre.
This growth is represented
by the thicker, lighter silver
rings. Then the hyphae change
orientation and grow at 90
degrees to the original growth.
This forms the dense but
thinner, darker bands. This is an
adaptation to water conservation
in these highly drought-tolerant
fungi, and gives them the
competitive edge.
The bands are gelatinous
as they form and it is thought
that this moisture is fed to theY
ou’veseenthemfor
surebuthaveyou
evenwonderedwhat
theyare?Thesehard,
black,hemisphericallumps
stucktodeadwood?Thevarious
commonnamesdon’treally
helpmuch:crampballs,King
Alfred’scakes,coalknobs.They
areinfacta fungus,butunlike
those productions of damp,
mouldering mulches, they are
specially adapted to exploit a very
different kind of habitat.
Like most fungi, Daldinia
concentrica are not obvious
to the eye for much of their
lifecycle. Living primarily inside
dead or dying ash trees, when
conditions are right and they
are ready to set spore, their
multitudinous and microscopic
filaments, called hyphae, come
together. Like strands that make
up a twist of rope, they knot
up and form the distinctive
stroma: the body of the fungus
that produces spores. Starting
as a small, flesh-coloured
protuberance that pushes
through the surface tissue or
bark of the infected dead limb,
it forms knobbly cushions and
clusters that eventually harden
and darken to form the purple-
black signature creations.NICK
BAKER
N
Hidden
GREAT BALLS OF FIRE
These curious fungi make e ective firelighters.
Bush craft enthusiasts might
know this fungus by yet another
epithet: tinder balls. This isn’t
simply because of its
similarities to a
piece of lumpwood
charcoal but
because its
desiccated nature
makes it an
excellent bed forthe sparks from a flint and steel.
A less proven use is to clutch one
in your armpit to relieve the pain
of menstrual cramps –
hence the name cramp
ball. While it’s inedible
to us, the fungus is
feasted on by the
tiny, rare concealer
moth Harpella
forficella.The fungi are said to be
the evidence of Alfred’s
infamous cooking
calamity that he hid
in the forest.D I D Y O U
KNOW?KING ALFRED’S
CAKES FUNGUS