How to identify mushrooms to genus By Fungus Ken

Many of you may not have heard of a series of books published in the United States in the 1980s by Mad River Press on How to Identify Mushrooms to Genus. I think most are out of print now, although you can probably pick them up second hand (at a price).

They describe useful characters for identifying the different genera and include helpful keys. However, for me as a beginner in the late 1980s one of the most useful concepts to get to grips with the different stature types for mushrooms.

The stature types are based on the following set of characters:

1. Presence or absence of a ring (the remnant of a membranous partial veil).
2. Presence or absence of a gelatinous, cortina-like, or fibrillose partial veil.
3. Presence or absence of a volva.
4. Consistency of the flesh of the stem.
5. Attachment of the stem, when present, to the cap.
6. Attachment of the gills to the stem.
7. Shape of the cap.
8. Type of cap margin.
9. Presence or absence of waxy gills.

Some of these characters are more important than others.

Here are some examples of the stature types:

I. Types with free or finely adnexed gills

amanitoid – volva present, ring present
vaginatoid – volva present, ring absent
lepiotoid – volva absent, ring present
pluteotoid – volva absent, ring absent

II. Type with either laterally or excentrically attached stem or stem absent

pleurotoid – gills attached, volva present or absent, partial veil present or absent

III. Types with centrally attached stem and attached gills

hygrophoroid – waxy gills, volva usually absent

mycenoid – cap conic to campanulate, ring absent, gills not decurrent, cap margin straight or decurved

collybioid – cap convex to parabolic, cap margin incurved to inrolled at first, gills not decurrent, ring absent

omphalinoid – cap broadly convex to plane, at times umbilicate, gills decurrent, ring absent

tricholomatoid – gills sinuate or notched, ring absent

clitocyboid – gills decurrent, sub-decurrent or arcuate-decurrent, ring absent

So how would you use the stature types? How do they help in narrowing down an unknown specimen?

One obvious benefit is that they are a handy reminder of some of the critical characters you need to keep in mind when you first make some notes of your new finds.

Let’s take an example. You find a mushroom which, when you turn it over, reveals gills that do not quite reach the stem (ie they are free) or they only just touch the stem (finely adnexed).

So what is its stature type?

You have four options:

amanitoid – volva present, ring present
vaginatoid – volva present, ring absent
lepiotoid – volva absent, ring present
pluteotoid – volva absent, ring absent

So having decided on the type of gill attachment you now need to decide whether there is a volva at the base of the stem and whether the stem has a ring.

Let’s say there was no ring and no volva. So the stature type of our specimen is pluteotoid. Fairly obviously this means having the characteristics of a typical specimen of the genus Pluteus. But there are other genera that could have free gills and no sign of a volva or a ring eg some species in the genera Lyophyllum, Bolbitius and Agaricus (although typically Agaricus would be lepiotoid - with a ring).

Essentially the stature type helps to narrow down the options, while also flagging up other possible genera that you might have overlooked.

The next step in identifying your mushroom to genus is to decide on the spore colour. You may be able to deduce this from the gills in a mature specimen, or you may have to take a spore print to be sure.

Colour of typical spore deposits in the genus:

Lyophyllum – white or whitish
Bolbitius – rusty brown to ochre
Agaricus - purplish brown to chocolate brown
Pluteus – pinkish to brownish-flesh-coloured

So if our mystery specimen had pink spores we would know it was in the genus Pluteus. Knowing the stature type we would also have already been able to rule out other genera with pink spores such as:

Volvariella – vaginatoid stature type (free gills, volva present)
Entoloma – a wide range of stature types but all with attached gills eg tricholomatoid, mycenoid, omphalinoid

(NB attached gills includes the attachment type known as adnexed. You may need to look very closely to decide the difference between properly adnexed and just free from the stem).


So next time you find a mushroom why not try it out. See if you can fit your specimen into one of the stature types. I've given some of the more common ones but there are others.

If we manage to sort out a WAB foray this Autumn, perhaps we could all have a go together.

Ken