A Quick Tour of the Amanita Genus

Editor’s Note:

This post was inspired by a reader who suggested that I take a bit of time on this blog to explain how to determine the genus of different sorts of mushrooms. One of the best approaches to learning wild mushroom identification, in my experience, is to become familiar with different genera of mushrooms and then to zero in on particular species that I wish to learn how to identify.

The advantage of this approach, in my opinion, is that it helps me look for parallels between the different mushrooms I find in the wild, which helps tie my knowledge all together and build little memory networks (memory mycelium?) where I can stash each new thing I learn. In this way, I increase my mushroom knowledge carrying capacity.

One of the "blushers," Amanita rubescens. Photo by Stu's Images. Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported.
One of the “blushers,” Amanita rubescens. Photo by Stu’s Images. Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported.

As with any other realm of inquiry, mycology is opaque and challenging at first, but once you gain enough generalized knowledge, you sort of hit a tipping point, after which learning new species, concepts, and mushroom behavioral traits becomes a lot easier.

This is why I emphasize genus identification in my own mushroom hunting endeavors, and I view it as the first step (but certainly not the last step!) in becoming acquainted with previously unknown species.

I will address other genera in the future, but I figure that genus Amanita, which contains both deadly and delicious mushrooms, is a good place to start. Please note that I will not be describing specific species in much detail, and if you are a novice (or even rather experienced) mushroom fanatic, eating Amanita mushrooms is not necessarily good idea. However, they’re damn pretty and super-interesting, and although identifying Amanita mushrooms to species might challenge you, pinpointing members of this iconic genus should present little difficulty.

Yours In Fungal Fancy,

Mushroom Anna

Amanita Mushrooms: An Overview

Of all the mushrooms in this wild world, fungi in the Amanita genus are among the most beautiful and classically “mushroomy.” All novice mushroom hunters really ought to learn how to recognize Amanita mushrooms right off the bat, because some of the most dangerous mushrooms in the world belong to Amanita. Specifically,  the death cap mushroom, Amanita phalloides and the destroying angel mushrooms, which include Amanita bisporigera, Amanita ocreata, and the Amanita elliptosperma group are poisonous North American mushrooms that can kill you, or at the very least cause significant liver and kidney damage. More on this a little later.

Most Amanita mushrooms are mycorrhizal, meaning that they partner with trees and plants. For a little more detail on how and why this partnering between fungi and plants occurs, check out this post about chanterelle mushrooms and their mycorrhizal associates. As a consequence of their mycorrhizal lifestyle, Amanita mushrooms are common in the forests of North America, where they pair up and trade resources with a wide array of deciduous and coniferous trees.

In North Carolina, there are many different Amanita mushrooms, and you can find them nearly anytime of year, although the majority of NC Amanita species fruit in the summer and fall.

Collecting and Handling Amanita Mushrooms

If you are interested in identifying any wild mushroom that you are unfamiliar with, it’s important to collect the entire specimen, including any flesh on or around the base of the stem. This is extremely important with Amanita mushrooms in particular, because their stem bases often hold the keys to the kingdom, identification-wise. In order to collect Amanitas (or other mushrooms) for identification, dig up the entire mushroom rather than slicing the stem off at the level of the ground.

Amanita phalloides, the death cap mushroom
The death cap mushroom, Amanita phalloides. Note the creamy ring on the stem, cup of tissue at the base, and yellow-white-green coloration. Photo by Archenzo. Licensed under Attribution-ShareAlike 3.0 Unported.

Be gentle when digging up Amanita mushrooms, because they often have what’s called a volva, which is a cup or sac of tissue at the base of the stem. These volvas can be quite delicate, flaky, and easily torn, and so careful collecting can mean the difference between a recognizable mushroom and a permanent mystery.

It’s also often very useful to take some photos of the Amanita mushroom in situ, because that can give you more information about what plants and trees were growing nearby (and possibly in association with) your mushroom, as well as what substrate the mushroom was growing on. For a rundown on wild mushroom photography for the purposes of identification, check out this post from a few weeks back.

Although some Amanita mushrooms are deadly poisonous, you do not need to fear handling them! The toxins in poisonous Amanitas are only dangerous when they’re consumed, so as long as you don’t eat it, you’re in good shape! However, take care to keep any unidentified mushrooms separate and apart from any wild mushrooms you plan to eat. Amanitas and other mushrooms break apart easily, and you don’t want to accidentally consume mushroom-bits from a specimen that’s no good for the dinner table.

Some mushrooms have a distinctive flavor that helps identification efforts. For example, some Russula mushrooms are peppery-hot like cayenne, and so nibbling a bit of the cap and spitting it out is helpful in identifying them.

However, I would not suggest taste-testing Amanita mushrooms. Although the risk of poisoning from this practice is vanishingly small, I heartily endorse a “safe, not sorry” approach to mushroom hunting. In addition, flavor is not particularly helpful information when it comes to positive genus-species identification of Amanita mushrooms. That said, it is helpful to smell Amanita mushrooms that you find because some of them do have a distinctive aroma. For example, a few species in Amanita smell like raw potatoes, which is helpful information to have if you’re trying to get a positive species identification.

Amanitas and Edibility

Although some Amanita mushrooms are edible and choice, I do not eat them at all, even though I am very familiar with some of them. I just figure it’s better to play it completely safe and just take pretty pictures when I find them. Generally speaking, Amanita mushrooms are not for the inexperienced or faint of heart. In fact, until you are confident and somewhat experienced, it’s probably a good idea to eschew eating any mushroom with white gills, a universal veil, or another signature Amanita feature just in case it’s a toxic species of Amanita.

Universal Features of Amanita Mushrooms

Amanitas come in different shapes, sizes, and colors, but there are a number of distinctive traits that they share. Here are the traits that are universal to the mushrooms in genus Amanita. Below, I will outline how you can go about discerning whether or not your mushroom has these traits, because the universal identification features of Amanita mushrooms manifest differently in different species.

A White Spore Print. Amanita mushrooms have white spores and (very commonly) pale or white gills. There are Amanitas that have colored gills, but nonetheless the spore payload is white in these species as well. Sometimes, it’s possible to determine the color of a mushroom’s spores simply by observing it in the wild. For example, the ringless honey mushroom, Armillaria tabescensgrows in dense clusters, and if you find mature specimens, you will find a dusting of spores on the caps of the mushrooms on the lower layers of the cluster. Amanitas, on the other hand, usually grow as individuals, so it’s often necessary to take a spore print in order to be certain of its spore color (instructions on spore printing is below).

Amanita jacksonii eggs
Baby mushrooms of the species Amanita jacksonii emerging from their universal veils. Photo by hrib. Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported.

A Universal Veil. Amanita mushrooms start out as little “eggs” of mushroom tissue that coats and shields the baby mushroom when it first emerges from the soil. This egg or protective layer of flesh is called a universal veil, and as the mushroom matures, the universal veil breaks apart, and there are often visible remains of that universal veil that remain on the mushroom. Specifically, Amanita mushrooms often have a cup or sac of flesh at the base of the stem called a volva, which is the remnant of this universal veil. In other Amanitas, the universal veil will leave traces of flesh on the stem itself, or more commonly as warts or patches of flaky flesh on the cap.

A Dry Cap. A good many mushrooms in this world have a cap that’s slimy and sticky. For example, the genus Suillus is full of mushrooms that feel like they’re coated in ogre snot. Amanita mushrooms, by contrast, have a naturally dry cap surface. If you find a mushroom and cannot tell if it’s got a dry cap because it’s raining or otherwise wet, just set it aside for a time and handle it once it has a chance to dry off. If you have a natural “ewww sliiiiimmmmmy” reaction to it, it’s not an Amanita.

A Note on Amanita Universal Veil Tissue

Although some Amanitas have very obvious cups or sacs of tissue at the base of the stem that indicate that the mushroom had a universal veil, other species in the genus have less clear signs of this feature.

For example, Amanitas in the subgenus Lepidella (which tend to be large and are very common in North Carolina) often do not have a cup or sac, but instead have bulbous stem-bases that are flecked with broken veil tissue, and sometimes have a distinctive rim at the top of the bulb. Other Amanitas have indistinct universal veil remnants that manifest as simply a few flecks of tissue at the bottom of the stem. Still other Amanitas have a cleft bulbous base, and mushrooms like Amanita muscaria have a stem-base that has curls of concentric flesh that hang off the stem in distinct little shags.

For a great series of pictures of the different types of stem-bases that can be found in Amanita mushrooms, I strongly suggest looking at Michael Kuo’s excellent treatment of the Amanita genus on Mushroom Expert. In addition, Mushrooms Demystified has good descriptions and drawings of the different sorts of Amanita universal veil remnants that is tremendously helpful in identifying Amanitas down to subgenus and ultimately species.

Other Common Amanita Features

Here are a few of the physical traits that a lot of Amanita mushrooms possess, as well as some manifestations of the universal traits that differ between Amanita species.

Partial Veil/Ring on the Stem. Many species in Amanita have what’s called a partial veil, which is a protective layer of flimsy flesh that covers a baby mushroom’s gills as it develops. When the cap opens fully, that layer of flesh breaks and leaves a ring (or annulus) of tissue on the stalk. Sometimes these rings are really fragile and can wash off in the rain, and sometimes they’re large and shaggy or skirt-like.

There are some Amanita mushrooms that lack a ring on the stalk. For example, the group of Amanita mushrooms commonly called grissettes lack a ring on the stalk. Other Amanitas have such dainty and delicate rings that they’re sometimes absent or very difficult to detect. However, anytime you’re looking at a possible Amanita mushroom, look for this feature. Please note that plenty of other genera of mushrooms have partial veils, for example Agaricus (the most common of which is Agaricus bisporus, the white button mushroom and portobello that you can hunt in grocery store aisles), Lepiota, Chlorophyllumand some species of Suillus. 

Warts, Bumps, or Patches on the Cap. As mentioned earlier, Amanita mushrooms have universal veils, and when the mushroom is mature, patches of that tissue may remain on the cap. The fly agaric mushroom, Amanita muscaria, is the easiest example of an Amanita that has patches. One of the cocorra mushrooms that grows in the western United States, Amanita calyptroderma, typically has a thick, fluffy patch of universal veil tissue that looks a little bit like a woolen skullcap or a small snowdrift.

Amanita calyptroderma
A California cocorra mushrooms, Amanita calyptroderma. Note the thick layer of universal veil tissue on the cap, large ring on the stem, cup of tissue at the stem base, and the pronounced striations. Photo by Alan Rockefeller. Licensed under Creative Commons Attribution-ShareAlike 4.0 International.

Other Amanitas, for example those in the Lepidella group, sometimes have warts or chunky protrusions on their caps. Although this feature is not a universal one in Amanitas, warts, bumps, and patches are three things that commonly occur in the species that make up the genus.

Cap Striation. A good number of Amanita mushrooms have vertical striations on the margin of the cap, which look like little stripes that run inward from the outer edge. Sometimes these striations are faint or difficult to see if you’re looking at a small Amanita, so have a handlens at the ready when inspecting little ones! A perfect example of a highly striated Amanita is the edible and beautiful Amanita jacksonii, commonly called Caesar’s mushroom, which grows abundantly in the forests of North Carolina.

Colorful Caps and Sometimes Red Staining. Although there are plenty of drab brown, gray, or off-white Amanita mushrooms, a good number of them are vibrantly colorful. Amanita mushrooms can be bright red, yellow, chestnut-colored, or multicolored (with the most common color combinations being yellow, red, and orange). Also, a few Amanita mushrooms stain red when they are handled, cut, or bruised. Again, this is not to say that all Amanitas bruise red and are brilliantly colored, but when you find mushrooms with these traits, you may wish to look at descriptions of Amanitas when you’re trying to get an identification.

Also, there are a good number of non-Amanita mushrooms that are brightly colored and/or stain red. For example, shaggy parasol mushrooms (including Chlorophyllum rhacodes, Chlorophyllum olivieri, and Chlorophyllum brunneum) stain reddish brown or saffron when they are cut. As for colorful mushrooms with white gills, there are dozens if not hundreds of different Russula species that have both features, but they completely lack a ring on the stem, universal veil tissue, striation, or anything else that would confuse one into thinking that they might belong to the Amanita genus.

Amanita Mushroom Toxicity Notes

Although there are many Amanitas that are not dangerous, a few of them are responsible for deadly or very serious mushroom poisoning incidents in North America. There are a couple different toxins, called Amatoxins (creative, right?), that exist in the extremely toxic species, such as Amanita phalloides (death cap mushroom) and Amanita bisporigera (one of the destroying angel mushrooms that grow in North Carolina and other eastern U.S. states).

One of the eastern U.S. destroying angel mushrooms, Amanita bisporigera. Photo by Dan Molter. Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported.
One of the eastern U.S. destroying angel mushrooms, Amanita bisporigera. Photo by Dan Molter. Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported.

I will do a more thorough treatment in the future on Amanitans, but suffice it to say it’s a bad, bad experience to be avoided at all costs. Typically, if one eats a poisonous Amanita that contain these toxins, they start to feel very sick within 6-24 hours of eating the mushroom. Vomiting, diarrhea, and extreme cramping is common. Then, once the mushrooms have been expelled from the person’s system, they often start to feel better. However, the amatoxins remain in the person’s body and are cycled back and forth between the victim’s gut and liver, like a deadly ping-pong match that causes serious liver damage that can lead to organ failure and death within a number of days.

There are some promising treatments on the horizon that might help save people who have experienced Amanita poisoning, and aggressive hydration and intensive care procedures are employed during the course of the person’s illness. In many cases, people survive Amanita poisoning (especially in the U.S., where good medical facilities can make the difference between life and death), but even in those instances liver and kidney damage are a grave risk.

This is why, in general, you should always keep a couple specimens of wild mushrooms that you eat, rather than consuming everything you find. If for some reason you get sick, it’s very helpful to be able to show hospital staff what you ate so that it can be identified and treated accordingly.

I have no intention of being an alarmist, as many hundreds of mushrooms are completely safe and have been eaten by people for thousands of years, but particularly when you’re eating a wild mushroom species for the first time, keep a couple extras in the fridge. Even in cases where you have an allergic reaction, having a specimen will help whatever mycological expert is contacted to consult with doctors if you need treatment.

Other Amanita mushrooms contain psychoactive chemicals, specifically ibotenic acid and muscimol. Amanita muscaria, Amanita gemmata, and Amanita pantherina are three such mushrooms, and they cause some very bizarre effects in some people, and historically some of these psychoactive mushrooms were used in shamanic practice. In addition, these mushrooms can contain muscarine, which is a toxin that causes excessive sweating, lacrimation, heart palpitations, stomach cramps, and an overall woozy, crappy sensation, although Amanita muscaria specifically does not contain much of this chemical overall.

Although historically Amanita muscaria has been listed in field guides as both deadly poisonous or edible and choice (depending on what author you are reading) in my opinion it’s somewhere in between. There have been several deaths attributed to consumption of Amanita muscaria, and even though one can remove the toxic compounds from this mushroom through vigorous parboiling and carefully removing all the boiling water, I simply don’t think it’s worth the risk or trouble. After all, there are many lovely mushrooms that are edible and do not need significant detoxification to be completely safe. Although rarely deadly, Amanita muscaria (and its relatives) will never be a part of my personal menu.

Amanita gemmata
The gemmed Amanita, Amanita gemmata, contains psychoactive compounds like its cousin Amanita muscaria. Photo by Andreas Kunze. Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported.

Best Practice for ID’ing Amanita to Genus

When I wish to determine whether or not a mushroom I’ve found is an Amanita, these are the steps I take. Although it might not get me down to specific species without some study, gathering the following information gives me a sure-fire understanding of whether or not I’ve got an Amanita on my hands.

  1. Collect the whole mushroom by digging it up. Inspect for universal veil remnants, specifically on the cap and base of the stem.
  2. Inspect for other common Amanita features: ring on stem, striations, warts or bumps.
  3. Look at the surrounding habitat for Amanita tree associates and make sure the mushroom is growing from the ground. If I am in a field with no trees, it’s less likely that my mushroom is an Amanita. (Note: a few Amanitas do grow out of highly decomposed wood, and some grow quite far away from their mycorrhizal associate).
  4. Inspect the gills of the mushroom and take a spore print. To do a spore print, simply cut the cap off the mushroom and place it on a piece of paper, foil, or glass and cover with a small bowl or tupperware to contain the spore deposit and keep the mushroom from drying out too much. In the case of white-gilled and other suspected Amanitas, I use colored paper, glass, or foil, so that I can clearly see the white spore deposit.
  5. Take a picture and verify my suspicions with mycological mentors and friends. Hit the books hard to get a species identification.

Concluding Thoughts on Amanitas

Although there’s a lot of fear and hysteria around wild mushroom hunting in North America, in general I think we could conquer our cultural mycophobia if people took the time to learn how to identify Amanitas to genus.

Many of the horror stories you hear about someone dying from mushroom poisoning can be attributed to Amanita mushrooms, which is sad because they’re also delightful species that command a lot of respect in the mycophile community because of their beauty and size. The problem is that they look so good to eat that sometimes would-be foragers try them and pay a high price. Ironically, Amanita phalloides is reportedly very tasty and is a favorite treat of mule deer in California, who are totally unaffected by them for whatever reason.

Although you may never in your life get up the nerve to try one of the edible Amanita mushrooms, they’re still a worthwhile group of mushrooms with astonishingly good information available on the different species. Unlike some genera of mushrooms that are a complete taxonomic mess, our emerging understanding of Amanitas is quite orderly (relatively speaking), which makes them a good genus to do a deep dive into when you’re ready to really get your mushroom identification nerd on. I know I certainly do, and I get a kick out of it!


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