THE CLUB FUNGI
|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:
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.
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.
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!
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.
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!
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.
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.
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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