I meet a lot of folks who, after I tell them that I am an avid forager, will say “I’ve always wanted to get into that but don’t know anyone who could teach me.” Truth be told, there were a couple times where someone who really knew their fungi well taught me about hunting them, such as oyster mushrooms and morels, but most of what I know I taught myself. Before getting into talking about mushroom identification, let’s zoom out. When I was about 18 years old I started to learn how to identify trees. By looking at leaf shape and learning technical terms like “sinus”, “lobes” or “pinnately compound leaves”, as well as examining bark, habitat, height, shape, etc. I was soon fairly easily able to identify many different trees on a hike through the woods. Understanding the hierarchical structure of taxonomic relationships and differentiating one species from another by honing in on a couple key specific subtleties was familiar ground for me. Having this skill, transitioning into mushroom identification was significantly streamlined. I would strongly encourage any beginners to mushroom identification to start with something more benign, like tree identification. If tree identification proves too difficult or frustrating or more of a chore than a fun hobby, then I would discourage that individual from pursuing the more difficult task of mushroom identification. If, on the other hand, you find tree identification to be enjoyable and as you walk through the woods, instead of seeing an ocean of green you see pin oaks, burr oaks, red pine, black spruce, green ash, etc. then you're going to love mushroom hunting! Real quick though, I need to lay down the heavy, and then we'll get into the fun stuff.
Real quick though, I need to lay down the heavy and make this disclaimer: this website cannot be relied upon as a comprehensive guide for a 100% identification of a mushroom. Identification articles regarding specific fungi posted on this site are meant to be supplements to, not replacements of, guidebooks or the knowledge of an experienced mushroom hunter. One more time: It is not meant to act as a substitute for a guide or a guidebook.
Also, I say this stuff not to sound condescending, but to make sure I've done everything I can to ensure the health, safety and happy hunting of my readers! So here goes: never eat a mushroom you are not 100% sure is what you think it is. In order to be 100% sure of a mushroom, you must have checked its habitat, season, spores, pores/gills, cap and stem color, texture, smell, etc. and also you must have cross references all identifying characteristics from minimum three separate guide books each with a different author. Not only should you positively identify what it is 100% but you should also 100% be sure it is not any other mushroom which it could look like, so you must identify both what it is and what it is not. A beginner mushroom hunter should first spend a significant amount of time hunting and gathering mushrooms of all kinds to practice identification in three guide books and should never eat any of those mushrooms. After a year or two of this practice, that person may be ready to begin successfully identifying and eating mushrooms they have harvested, though I would recommend doing so only after completing a certification course.
Now on to the fun stuff (!)...
All mushrooms are intended to do one thing: spread spores. Much like all fruit (apple) is meant to spread the seed of its mother plant (apple tree), all mushrooms are meant to spread the spores of its mother fungi, also called mycelium (the fungal equivalent of the apple tree). There are three different ways that mycelium grows: as a mycorrhizal, saprophytic or parasitic organism. Mycorrhizal fungi, which is a dense network of threadlike roots (mycelium) growing underground in the soil, forms symbiotic relationships with shrubs and trees around it. While mycorrhizal fungi is associated with living plants, helping them to survive, saprophytic fungi, on the other hand, is associated with dead plants, and grows on dead logs, leaf litter and other dead organic matter, assisting in the process of decomposition. Finally, there are parasitic fungi, which provide the go between for life (mycorrhizal) and death (saprophytic). These fungi take advantage of living organisms by attacking them and depleting them of their resources, which can sometimes (or often) kill the plant, tree or even animal which the fungi has chosen as its host species. Most of the edible mushrooms that will be discussed on this blog will be either mycorrhizal (grows in soil) or saprophytic (grows on dead matter--usually wood). This is important because a mushroom you think is mycorrhizal but appears to be growing on a tree is clearly not the mushroom you thought it was! Note: sometimes dead wood or decaying organic matter is buried in the soil and a saprophytic mushroom can appear to be a mycorrhizal mushroom, so be careful. It is rarely the other way around.
Anatomy of a (Agaricales) Mushroom
Most people think of two parts of a mushroom: the cap and the stem. For most mushrooms these are the main two parts, and already we have taken a step towards identifying the mushroom: is it a member of the order “Agaricales”? Agaricales includes almost all mushrooms growing from wood or the ground with a central stem bearing a cap, underneath which are spore disseminating structures, typically gills or pores, from which spores fall. Spore droppers, subdivided as “Basidiomycota” is the Division which includes agicales. Let’s dive into some of the parts of these mushrooms.
Cap (aka Pileus)
Typically, this is the first part of the mushroom that is seen. Of course the cap is the top of the mushroom. Though most are round, some will be sunken in the middle (concave), others will be exceptionally pointy forming almost a cone. Some caps have remnants of a veil on them leaving white “patches” or “scales” on top of the cap. The “skin” or surface or the cap can have varying textures, such as slimy, dry, velvety, etc.
Stem (aka stipe or stalk)
The stem of the mushroom should be pretty straightforward, right? (Get it? Ha!) But really, this is mostly true, but they can have some nuance to them. Some stems are very long and skinny (mycena family), whereas others are short and very fat (boletus edulis). Some stems are hollow, others are very dense, others are hairy. Some stems have a delicate bit of tissue forming a ring around them close to the cap (remnant of a veil). These are all important features to pay attention to. Alternatively, there are a few species of agaricales growing on dead wood that lack a stem, such as angel’s wings.
Veil
Now we begin to get into some of the less familiar territory of mushroom parts. Mushrooms grow in a variety of manners. Sometimes the cap of the mushroom begins as a sort of ball around the top of the stem. As the mushroom grows, the ball begins to open up and outwards and the cap separates from the stem leaving behind evidence of its former union with the cap. A “universal veil” is similar to this, however it includes not just the cap and the top of the stem, but the whole mushroom. This will then leave an egg shaped structure (called a volva) at the base of the stem, as well as typically still leaving a ring around the stem. Both the amanita and cortinarius families are notorious for having several deadly poisonous species within their ranks and many species from these families can be identified in part by their veils (or evidence of a former veil).
Spore Disseminating Structures
Gills
This leads us to the next anatomical feature: the “spore dissemination structure”. In the order Agaricales, these are either gills or pores. Gills look like what they sound like, little sheetlike blades underneath the cap of the mushroom. Blades have a variety of characteristics. Some grow completely hanging off the cap without having any connection to the stem. This is called a “free” gill. Some grow with gills that do connect to the stem but have a slight upward indentation, called “adnexed”. Of course, other blades connect directly to the stem, called “adnate”. Some gills are thicker and, as they go outwards from the stem, may even fork or branch into two or more gills. False gills, specifically associated with chanterelles (cantharellus cibarius), are more like wrinkles. They can sometimes appear like a thicker gill, but will run down the stem without uniformity and will often fork and then reconnect forming ovals or long narrow brackets.
Pores
Pored mushrooms, in the Agaricales order, include the families suillus, leccinum and boletus, among others. Underneath the cap of a pored mushroom will be a tissue appearing to have a sponge-like texture. Depending on the species, some of the pores could be so small as to be almost invisible, leaving the underside to appear to have a soft, often velvety surface. Others have large gaged pores and might even appear to look more like a dense netting is at the base of the cap.
Teeth
Toothed mushrooms release their spores from a more unusual structure: teeth hanging off the underside of the mushroom’s cap. They appear almost like hundreds of very tiny stalactites. There are only a few species within the Agaricales which feature these structures, particularly dentinum repandum.
Spores
One of the most unobvious but important details for accurate identification of any mushroom is to know a little bit about the mushroom’s spores. The minimum needed for an accurate identification of a mushroom is called a “spore print”. To make a spore print, take the cap of a mushroom and cut the stem completely off so that the mushroom can lay as flat as possible. Place the mushroom over some paper (ideally with both a black and white side and relatively thick paper, like construction paper). The spores will fall from the pores or the gills and land on the page. If white, yellow, cream, etc. the spores will be more obvious on the darker colored sheet of paper. If black, chocolate, purple, brown, etc. the spores will be more obvious on the white sheet of paper. The spore color for some species is the easiest way to rule out potentially poisonous look-alikes. Further, an expert mycologist or even a serious mushroom hunter with a knack for taxonomy will gaze upon this spore print under a microscope. Spores have different shapes and lengths, depending on the species and for some of the more obscure mushrooms, this can be the only way to tell the difference between one species or another. Personally, I never consume any mushroom which requires this step in order to be certain of the species, as I could never feel 100% sure of my identification if I’m relying on just one microscopic characteristic.
A Word on Other Varieties of Fungi
The above anatomical mushroom parts describes the typical mushrooms that most folks hunt for. There are a few commonly hunted species not included in the Agaricales order which are prized edibles or which are called “agaricales” without adhering to the strict base, stem, cap structure most of those mushrooms adhere to.
Staying in the Agaricales order, the first of these nonconformists are shelf fungi. Among the shelf fungi are the polypores such as chicken of the woods, the gilled oyster mushrooms, and the toothed coral fungi, such as the Lion’s Mane. All of these include excellent edible species.
There are also the jelly fungi which includes a few prized edibles and some of the most interestingly shaped mushrooms. Lastly, the puffball, which looks like what it is: a round ball growing from the ground. Some are as small as little ping pong balls growing from dead logs, while others are as large as basketballs growing from the ground. Many of these are edible though there are also some poisonous varieties to look out for.
Straying outside agaricales and even outside the broader subdivision of Basidiomycota, we venture into the world of the Ascomycota. There are two highly prized mushrooms, perhaps the most prized mushrooms in the world, which are members of this more unusual division of fungi: morels and truffles. Ascomycota are so named because rather than forming and dropping their spores from external structures (basidia), these mushrooms form and release their spores into the atmosphere via internal sacs (asci). The morels including true morels (morchella genus) and false morels (gyromitra genus) form bulbous, brainlike mass atop a stem, not unlike a form of a cap, containing its ascii within this membrane. Truffles grow underground, looking and acting much like a small potato. These fungi are some of the most prized in the world and can be sold for as much as 80 to over a thousand dollars per pound!
Closing Thoughts
When identifying a mushroom, start by thinking about the biggest stuff and gradually zoom in. Time of year, tree type/habitat where mushroom was found, part of the country you are in, etc. Then go to the next most macroscopic set of features growing on ground or wood, stem, cap, shape, color. Then hone in on smell, texture, spore print and, if necessary, spore shape. Check out the following article for how to make a positive ID of a mushroom (Beginners part 2).
If you are new to mushroom hunting, use this as a helpful guide for what to start looking for. Please feel free to become a member and check my posts or other folks comments to familiarize yourself with a variety of mushrooms. Or take a picture and email it to me directly at ed.joice@mnforager.com.