There are several locations near my home where wild mushrooms emerge in the autumn. I’m always pleased to see the fungi and enjoy photographing them. I highlight two of the mushrooms in this article and discuss the mycelium that produces them. The fly agaric is poisonous, but it has cheerful and bright colors that are reminiscent of Christmas. The shaggy mane is covered with scales when it’s young. As it digests itself and releases its spores, it turns into an inky mass. This gives it the alternate name of inky cap.
Mushrooms are interesting and are important in the life of many species of fungi. They produce the spores that enable the organism to reproduce. They are created by the part of the fungus that is present beneath the soil surface and is known as the mycelium. Not all fungi produce noticeable mushrooms, but they all reproduce and they all exist as a mycelium, with the exception of yeasts. Yeasts are a special category of fungus with some unique features of their own.
The Fly Agaric
The fly agaric (Amanita muscaria) often appears under trees, like the ones in my photos. It’s an attractive and easily recognized mushroom. The cap is usually red with white flecks on the surface. One variety has an orange cap. A loose ring of white tissue is present on the stem, or stipe. The ring is known as the annulus.
As in many mushrooms, the young form of the mushroom that emerges from the substrate is in the button form, which is shown in the photo below. The cap gradually opens up as the mushroom matures, revealing the gills underneath. The broken covering of the gills that was present in the button stage becomes the annulus. The gills produce and release the spores.
The poisonous effects of the mushroom depend on the amount that’s eaten and on individual sensitivity. It contains both neurotoxic and psychoactive chemicals. Deaths from ingesting the mushroom are said to be rare but do occur.
The fungus that produces the mushrooms lives symbiotically with some trees. The hyphae grow over the tree’s roots and exchange materials with them. The roots obtain nutrients that the hyphae have absorbed from the soil and the hyphae receive sugars that the tree has made by photosynthesis. Fungi don’t perform photosynthesis.
Shaggy Manes or Inky Caps
Shaggy manes (Coprinus comatus) are thought to have received their name due to the appearance of the young mushrooms. These are covered with scales and reminded earlier people of a lawyer’s wig. The mushrooms are white and elongated.
Within a couple of days, a major change occurs in the mushroom’s appearance. The oval form unfurls to produce a typical mushroom shape. As it does this, it turns black, and the edges of the cap drip a black, ink-like substance. The process is called autodigestion. As the cap is digested, the spores are released. Wind sometimes blows the ink and the spores to a new area. The mushroom is often referred to as an inky cap due to its appearance during autodigestion.
White shaggy mane mushrooms are edible. It’s vital that anyone collecting wild mushrooms to eat is absolutely positive about the correct identification of the fungus. Some mushrooms are poisonous, and some are deadly. In addition, if you’re using a reference source for research, you should look at the scientific name of the mushroom being discussed. The common name “inky cap” refers to several species, for example.
If you decide to collect wild mushrooms, it’s a good idea to do it with an experienced forager for a while. The mushrooms of a particular species can sometimes have an atypical appearance, which means that a poisonous mushroom may be confused with a safe one.
I took the two photos of the shaggy mane mushrooms shown above on a Friday. The photo of the inky cap form shown below was taken in the same patch of land on the following Monday. No white mushrooms remained at that time. The change in the mushroom’s appearance is dramatic.
Hyphae, the Mycelium, and Mushrooms
The body of a fungus consists of thread-like structures called hyphae. The threads branch and intermingle to form a mass called a mycelium. The hyphae in the mycelium release digestive enzymes into their substrate. The products of the digestion are then absorbed by the hyphae and nourish the fungus.
The mycelium that produces the mushrooms that I see in nature live in the soil, but they grow in other suitable environments. These include food eaten by humans, where the result may be decayed and inedible food. Some species of fungi can infect humans and cause disease. Fungi are sometimes helpful, however. For example, specific types are eaten as food. Some produces medicines that we can use, such as the antibiotic penicillin and the cholesterol-lowering drug lovastatin. Some are useful in other ways, as I describe below.
Mycorrhizae and Trees
Another interesting aspect of fungal mycelia is their growth on tree roots and on the roots of some other types of plants. Many fungi grow in this way, The association between fungal hyphae and a tree’s roots is known as a mycorrhiza.
Ectomycorrhizal fungi cover the root tips of a tree, as in the photo above. They also penetrate the roots and extend round the outermost cells, forming what is known as a Hartig net. Endomycorrhizal fungi exist almost completely inside the root tips. Both categories contain subcategories.
The Wood Wide Web
Hyphae are thin, but they can be long. They also branch. One tree is often connected to a nearby one by fungal hyphae. The connections between the fungi and the trees in a forest can form an extensive network sometimes known as the “wood wide web.”
Researchers are discovering that the chemicals transferred by the hyphae in a network of plants are not only nutrients. Some of the chemicals appear to be signaling molecules. Scientists have shown that some plants communicate with another one by means of signaling molecules and produce specific effects.
The hyphal connections between plants can be surprising and sometimes complex. In the illustration below, the hyphae from the fungus are connected to both the autotrophic plant and the mixotrophic one. An autotrophic plant produces its own food. A mixotrophic plant makes some of its own food and obtains the rest from other sources. In the illustration below, it’s able to steal food from the autotrophic plant through the hyphae.
Human Use of Fungal Mycelia
Some enterprising investigators are growing and using fungal mycelia for human purposes. The mycelia are used for food, packaging, clothing, and even for construction. A compacted mycelium can be used in the production of meat substitutes. The material is also used as a substitute for Styrofoam, a substance that is not biodegradable. At least one company is using fungal mycelium to create faux leather. A fungus named Fusarium venenatum has an unusually high protein content. It’s used to make mycoprotein for vegan “meat.”
Fungi are interesting biologically. They are also interesting because of the ways in which they can help us. Although some can be harmful for us, many aren’t. The mushroom and/or the mycelium of the fungi can be useful, depending on the species. We might soon discover more ways to use the organisms.
- Fly agaric notes from The Wildlife Trusts
- Wood wide web news from Science magazine
- Human use of fungal mycelia from Scientific American
- Mycelia for clothes from the BBC (British Broadcasting Corporation)