Most but by no
means all of the most interesting fungi we find in our neighborhoods are club fungi. As
the drawing at the right indicates, the name "club fungi" derives from the fact
that in this group spores, more technically known as basidiospores,
are produced on microscopic, club-like structures called basidia
(singular basidium). In fact, in technical texts this group is usually
referred to as the Basidiomycetes or Basidiomycota..Basidia
cover part of the fungus's reproductive structures. In gilled mushrooms (one is
illustrated below), the gills are covered with them. The above diagram shows a cross
section of such a gill. Basidospores detach from the basidia and drift down out of the
gills, and then are dispersed on wind currents. Basidia occur elsewhere on the fruiting
bodies of non-gilled fungi. You might want to compare this diagramm showing basidia and
basidiospores with the diagram showing asci and ascospores on the sac
fungus page .
Here are some of the kinds of club fungi we can look for:
Gill Fungi
These have gills under their caps -- the slender items
radiating from the stem in the photo at the right. Millions of spores are produced on
these gills and fall downward, to be spread elsewhere on the wind.
Most but certainly not all gill fungi have the classic "mushroom shape" like
the one at the right, and most but not all of the best ones to eat are gill fungi
-- also most of the ones that can poison us. By the way, the mushroom at the
right is a member of the genus Lactarius. Among its identification features are
the fact when the gills are injured they produce white latex or "milk," and
injured tissue turns brown, as the image shows.
Pore Fungi
Not all "mushroom shaped"
mushrooms have gills under their caps. The one at the right obviously have pores, and
spores fall from these pores the same way they do from gills on gill fungi. This pore
fungus is a member of a large, common mushroom genus worth knowing, that of "the
bolets," of the genus Boletus. One reason to know this genus is because it
is common, and another is because many species in the genus are good to eat! This
particular bolet, by the way, shows an important characteristic that some bolet species
show. That is, its flesh "bruises blue." That dark splotch on the cap's top
right is the "blue bruise." A few seconds before I pressed my thumb there, that
area was yellow like the rest of the cap. Many bolet species do not bruise like that.
Stinkhorns
The Stinkhorn at the right, Mutinus caninus, which is 5 inches high (13 cm),
often appears growing in the mulch I spread in my organic garden in Mississippi. If you
break open the thing you see that it's mostly empty air, just a thin shell a little like
orange Styrofoam. The whole thing is sticky and moist, and the top part appears to be
covered with a dark, greenish-brown, slimy goo that stinks! In fact, flies land
on as if it were a pile of dog-doo, and it smells like it could be just that. This fungus
stinks and draws flies for a reason, however, and that's because the greenish-brown stuff
is composed of basidia and basidiospores. Therefore, when flies fly away with the stuff
sticking to their legs, they're helping the Stinkhorn send its reproductive propagules
into new territory. The flies are "planting" new Stinkhorns everyplace they
land. Notice that the orange stalk arises from something looking like an egg. That's
typical of the various Stinkhorn species. When I first found some "unhatched"
Stinkhorn eggs I thought they were big turtle eggs, so I was pretty surprised when I let
them stay where they were, and Stinkhorns emerged! Neither the egg nor the Stinkhorn stalk
are poisonous, but I can't imagine anyone wanting to eat them!
Coral Fungi
The common fungus shown at the left usually grows in
woods or on decaying logs, and many of them really do look like fantastic organisms you
might find in a tropical coral reef. Often they are brightly colored. The one in the
picture is only about an inch high (2.5 cm) but some species get much larger. Basidia
occur in a continuous layer covering the surfaces of the fungus's erect branches. Though
most species are fleshy and edible, not many people pick them to eat because of their
small small.
Puffballs
The
item at the left is a "true" puffball, probably the genus Lycoperdon.
In puffballs, spores form inside the baglike structure, then escape through a hole at the
top. Such a hole is clearly visible in the picture. The yellow-framed inset in the image's
lower left side shows a cross-section of the puffball. There's not much to see in this
cross-section because earlier it was filled with spongy material that developed lots
spores, and now most of the spores are gone, leaving the
puffball as if it were an empty bag. The picture at the right shows a special kind of
puffball, the Earthstar, genus Geastrum. This was found along the forest trail
leading to my little home in the woods. At first the Earthstar looks a lot like the Lycoperdon,
but then its outside "rind" splits and opens up, its "arms" curling
back in the way you can see, and this reveals a regular puffball inside, which develops
spores inside it, and those spores escape through a hole in the top just as in regular
puffballs.
Bird's Nests Fungi
The
tiny, tiny objects at the right are appropriately known as Bird's Nests -- they are
members of the Nidulariales. Each of the "nests" is barely large enough
to hold a BB. The little black "eggs" in the "nests" (the eggs are
technically called "peridioles") are at first covered by white membranes, but at
maturity the membranes rupture, exposing the eggs to open air. Then raindrops splash the
eggs out of the nest. These eggs contain spores which will germinate and form new fungal
bodies. Bird's Nests are not particularly rare or exotic. I happened to notice
these one morning growing in the old, wet ashes around my campfire as I prepared
breakfast!
Jelly Fungi
The
Jelly Fungus growing on a dead twig at the left, shown about double its natural size, is a
very common but also very strange fungus. It has no stem, no gills or visible pores --
it's just a hunk of jelly-like substance that grows exactly as shown in the picture. This
fungus is edible, though most people would say it doesn't taste like much. In the Orient
it's called "Wood Ears" and is used as a flavoring for soup. So why is this a
club fungus? Because jelly fungi also produce spores over the surface of their bodies on
microscopic structures very much like those found on the surfaces of gills beneath regular
mushroom caps.
Rusts
At the right you see a much-enlarged picture of a
fungal rust looking like orange-yellow... well, rust... on the
undersides of some Oxalis leaflets. About 2000 species of rust are known and all
are parasitic on flowering plants or ferns. No other group of fungi is as dangerous to
agricultural and horticultural crops. The rust in the photo is Puccinia oxalidis.
The spore-producing "fruiting bodies" of this rust are tiny black specks you can
barely see scattered here and there across the leaflets.
The life histories of rusts often are mind-bogglingly complex, often with the
fungus spending part of its life on one kind of plant, then another part on a completely
different kind of plant. For example, right behind my trailer there's a young Loblolly
Pine about 20 feet tall. The image at the left shows the swollen, blistered item appearing
on the trunk at about the 10-foot level. It's about 2.5 inches thick (6 cm). This is
Fusiform Rust, Cronartium quercuum f. sp. fusiforme. When you knock
against the trunk, a cloud of orange powder is released from the blisters. This powder is
composed of tiny aeciospores. These aeciospores land on oak leaves and
later in spring pustules known as uredia will appear on the oak leaves'
undersurfaces. During late spring or early summer, brown, hairlike structures called
telia will form on the oak leaves. These telia will produce teliospores
which will germinate into basidiospores, which will infect a pine and
cause the infection shown at the left. This is a serious disease for Loblolly and Slash
Pines in the US Southeast. Infections that occur on the main stem within the first 5
years of a tree's life normally cause tree death. My Loblolly Pine is about five
years old, so it will probably die. Infections that occur on older trees weaken stems and
trunks, resulting in wind breakage at the canker.
This
is "real smut on the Internet," so we'll see if the "smut filters" let
the page show up on your computer. The black masses among the much-enlarged grass flowers
at the right is real smut. In fact, smut is such a common occurrence on this particular
grass that its common English name is Smutgrass. It's Sporobolus indicus. Smut is
closely related to the rust fungi, and it typically shows up as black and dusty masses,
just like in the picture. The blackness is caused by black spores. Among the smuts, when
the hyphae parasitizing the host plant are ready to reproduce, the hyphae's cell walls
melt, or "gelatinize," and the cells' contents changes into spores. Once the
cell walls are completely disintegrated, the spores float away on wind currents. This
special kind of spore is called a teliospore and it's sort of a resting
stage. The teliospore may fall onto the ground and perhaps at a much later date, when
environmental conditions are good, it germinates to produce a long tube-like thing, and
that's the basidium, which we've already met. The basidia -- just as they
would on a gill or pore fungus -- then produce basidiospores, and of course new hyphae can
germinate from the basidiospores.
Stem Rot
You know some fungi more by how they affect their host
than by how the fungus itself looks. For example, at the right you see a cross section of
a broccoli stem afflicted with a stem rot fungus. Here you don't really
see the fungus, but with a little experience you know that the fungus is there. In the
picture you can see that the bottom part of the stem is firm, green and healthy, but a
brown, mushy and very stinky dead zone is working its way down the stem. In fact,
the stem already has deteriorated so much that the entire top of the plant has fallen over
and become detached from the stem! You see a few green sprouts gamely trying to survive,
but their days are numbered. The unseen fungus is sending its hyphae into more and more
living cells and as they die they turn brown, mushy and smelly. I think that the name of
this fungus is Thanatephorus cucumeris but I'm not sure. This fungus really hurts
my garden crops of broccoli and cabbage. It's hard to get rid of this fungus because its
reproductive structures persist in the soil for years!
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