The Amanita Family

Amanita is one of the more charismatic genera of gilled mushrooms. One section of it is responsible for over 90% of mushroom poisoning fatalities. Another section contains a mushroom that was such a prized edible that its Latin name, A. caesarea, reflects how esteemed it was by the Roman nobility. They have a great diversity of forms and colors, and they have a much better base of available information on them than many other genera, thanks in large part to the long-standing investigations by Rod Tulloss.

Amanitas have a distinctive set of features: white spores, a universal veil and a partial veil. The photo below shows how they develop:

The baby mushroom starts out completely enclosed in a membrane known as a universal veil. On the left, you can see the mushroom breaking out of the universal veil as it grows. The universal veil remains behind as a cup at the base of the stalk, and sometimes as patches on the cap (see mushrooms second and third from the right). The partial veil is a membrane that covers the gills in the developing mushroom. In the last two mushrooms at the right, you can see that as the cap expands, it breaks free of the universal veil, which is left behind on the stem as a ring.
 
Things are not always this simple and obvious. In some Amanitas the veils are powdery or crumbly, so they don’t always persist into the adulthood of the mushroom. For instance, in this mushroom from Section Amidella the partial veil has been shredded and smeared during the mushroom’s growth until it now persists only as some irregular, darker-colored bands on the mushrooms stem, and intermittent shags hanging from the edge of its cap:
In other Amanitas, in section Validae for example, the universal veil material at the base of the stalk crumbles away almost completely. But often, it is still recognizable:
Here, the universal veil material is yellow, so it’s easy to spot in the flakes on the cap, and strewn over the base of the stalk (and from the color, it’s easy to realize that the material in these two places is the same stuff). But in other cases, where the powder is white, or it crumbles away entirely, it’s not so easy to put two and two together.
In many cases, detecting the presence (or former presence!) of a partial and universal veil is not easy! But noticing the characters of these features is essential to identifying the mushroom.

The Amanitaceae (the genera Amanita and Limacella) are a fairly distinct family. They can be recognized in the field by looking for the features discussed above. Or if you have a microscope, they are the only gilled mushrooms with divergent gill trama. Many of them have a characteristically elegant and graceful stature. Many of them do not! But once you’ve seen some from a given group, it’s usually easy to recognize others.

Limacella, Amanita’s slimy twin

 

Limacella, the other genus in the Amanita family, contains mushrooms that look just like Amanitas but have a universal and partial veil that are made of slime. Otherwise, they are biologically just like Amanitas. Here we see the slimy partial veil of a Limacella that otherwise looks just like a destroying angel. They are usually quite rare and there isn’t good information on many of them; so we’re not going to treat them here.

Classification and Identification tips

The genus Amanita is currently divided into seven sections, in two subgenera. Mycologists do this a lot with large genera – they divide them up into groups that are each more similar, and more manageable in size. It’s like 20 Questions – first you separate things into groups based on shared characteristics, and then you narrow things down further. The official difference between the two subgenera is whether or not their spore are amyloid. I’m not emphasizing that, because very few of you will test the spores, and it’s actually not that helpful in identification except for testing a few species that have lookalikes in the other subgenus. The character of the universal and partial veil are the most important features for finding what section your Amanita is in.

There are some colors that are surprisingly widespread in the genus. There is a dull pink or brownish pink that is most officially associated with the “blushers”, mushrooms in the Validae that bruise this color. But such bruising is also characteristic of the Amidellas, which may also have universal veil powder that turns this color; and two other mushrooms in different sections also start out covered with a layer of universal veil material of this color. There are also other colors that an Amanita may bruise or age: brown or lilac, for example.

Some cap pigments with distinctive behaviors are also widespread. There are some Amanitas in the species clusters around muscaria, caesarea, and flavoconia that start out red and fade – starting at the edges and working its way inward – to orange and then yellow. Certain waxy caps are the only other mushrooms in North America that do this, and they are much smaller (and lack universal veil flakes).
Likewise, there are a few different groups (the panthers, the blushers, and the brunnescens/citrina cluster) whose colors each range from dark brown to very pale yellow (with even some all-white versions tossed in). So you may find Amanitas that look the same except that their cap colors fall at different places along this continuum; in this case, you are probably finding a bunch of the same species, and they will have to be distinguished from other Amanitas with the same range of colors but the features of their bulb at the base of the stalk.
Some Amanitas also have a characteristic smell. The most widespread one is sickly-sweet, like rotting meat. It is mainly associated with Lepidellas, but Amanita phalloides can have it too. It’s fairly unique among mushrooms, but it has been implicated in poisonings where inexperienced collectors took this to be the cinnamon/spicy + stinky smell of the matsutake.
The other smell that some Amanitas have is that of potatoes. Usually these are Amanitas with a basal bulb, and scratching the bulb is the best way to get the smell.

Subgenus Amanita

This is the group with inamyloid spores. That is the official difference between the two subgenera; but there are also a few unofficial ways to figure it out. The Amanitas in this subgenus get striate much more quickly; so if your young mushroom is striate, try here first. Likewise, the Amanitas with free gills are here.
There are several Amanitas with bright warm colors – red, bronze, yellow, orange – here, although there are also a few in the other subgenus. Also, most of the conifer associates are here. There are hardwood-lovers here, also; but if your Amanita is growing under conifers, check here first.

Section Amanita

This is the type section for the genus. It is centered around the type species for the genus, Amanita muscaria. The species right around muscaria have a unique stack of cogwheel-like rings at the base of the stalk (vestigial in one species) and a flowing, skirt-like ring. They are usually warmly colored – bright red, bronze, orange and yellow – but there is one species in cold environments that is dark brown.

The other major group in section Amanita are the so-called booted Amanitas – the ones that have a round, rimmed bulb at the base. The top of the bulb may feature a ring of universal veil material that is folded over on itself, like a rolled-up sock; or the universal veil may leave a slight rim on the basal bulb, or a tight ring or two around the base of the stalk (like the basal rings of muscaria, but not jagged). Rarely, bits of the universal veil may remain as small patches on the bulb. The cap is likely to be a pale/dull yellow or deep brown, without shades of purple or lilac (which again is a Validae feature).

There is also a third, smaller group of powdery Amanitas in this section. Both of their veils are so powdery that the universal veil (and often also the partial veil) doesn’t survive the mushroom’s expansion, except as a few flakes in the center of the cap, or as powdery smears on the cap or the small basal knob.

Section Caesareae

These are brightly colored mushrooms that have the red, yellow and orange caps mentioned above, but can also be a shiny copper or bronze color. Also, the gills or partial veil may be yellow or orange. These Amanitas have both a cup at the base and a ring on the stem.

Section Vaginatae

These Amanitas have a cup, but no ring. Sometimes the cup mostly crumbles away, or is wrapped tightly around the stem, so it is not obvious. The cap is likely to be deep brown, grayish brown, or a brownish yellow called fulvous, which is supposed to be the color of a lion.

Subgenus Lepidella

This group has amyloid spores. Almost all Amanitas are mycorrhizal – symbiotic with trees that they grow near – but there are a few in section Lepidella that occur in grass. The remainder are mostly mycorrhizal with broadleaf trees. The Amanitas in this subgenus tend to have attached gills and start out life not being striate – though just about any mushroom can get striate when it gets old.
Completely white Amanitas are much more likely to go here. The chunky ones would be in Section Lepidella, and the more gracile ones (the destroying angels) are in Section Phalloideae.

Section Lepidella

Almost all Lepidellas are big, chunky mushrooms that are completely white, although some are dark brown or charcoal on top and one is a powdery dull pink all over. There are actually all-white varieties in just about every section, but this is the one where most of the species are supposed to be white.

They usually also have a scaly bulb that roots into the ground. Some species have the thickest universal veils in the genus; so if your Amanita has cap flakes that are pointy, or look like they’re piled up, it’s a Lepidella. All sorts of universal veil textures are possible, though – there are also some species with a powdery veil.
Note that when we call a mushroom “a Lepidella”, we mean a member of this section, not a member of the subgenus.

Section Phalloideae

The mushrooms in this section have both a cup and the base and a ring on the stem. For our purposes, there two main groups: the all-white destroying angels, and the greenish-brown-capped death cap.

Section Validae

This section is rather large and complex. All the members have a skirt-like ring. But the stem base may have a number of forms, and this can lead to confusion with other sections.

The blushers are a group of Amanitas that may be various shades of brown or gray on top (or even completely white) that slowly bruise a dull brownish red. It may be a brighter shade at first, or in insect tunnels, but will fade. Often the cap and stem develop stains of this color on their own.
The stem base is quite distinctive — or rather, it’s distinctively non-distinctive among Amanitas, being merely a slight swelling that extends a little into the ground. There are usually clear universal veil flakes on the cap that mark it as an Amanita; this plus the simply swelling stem base mark the blushers as well as anything else. If your mushroom “blushes” but has a cup at the base and no ring, it is an Amidella.
Another cluster of Validae species is the citrina/brunnescens group. These have a cap color ranging from pale yellow to dark brown, often with tinges or irregular streaks of red, purple, or lilac. They all have the potato smell – scratch the bulb and check. The bulb is soft and cottony on the citrina side of things, and is firm (like the stalk) but cleft vertically on the brunnescens side. The bulb may have scattered, irregular flakes of universal veil material on it. It won’t have the basal rings as in section Amanita.
There is also a small cluster of species around Amanita flavoconia. These are mostly small, delicate woodland mushrooms whose cap is some shade of yellow, orange or red. Their universal veil material is yellow. The base of the stem is slightly rounded, sometimes to the point of becoming a small, rounded bulb.

Section Amidella

Amidellas have a conspicuous cup at the base of the stalk, and this cup is rather leathery and tougher than the cup on most Amanitas. It also has a tendency to look as if it is dirty. The partial veil, on the other hand, breaks up easily and is left as a bunch of tiny, sticky shreds on the stalk, rather than forming a ring. Like the blushers, the Amidellas tend to turn a dull brownish pink, but it’s more of a surface thing, and also a universal veil sort of thing – so your mushroom may have pinkish powder or patches on the cap from the universal veil remnants.
This is a group of mushrooms that are easy to place within this section, but hard to identify to species, not least because there are only a few official species concepts in use.