Let us dive further into the phylum Basidiomycota, specifically in the class Agaricomycetes and
the order Agaricales.
In the previous tutorial, we discussed a number of species in the family Agaricaceae.
Over the next few tutorials, we will discuss many more species and families within the
order Agaricales.
By doing so, we will see examples of fungi that encompass a wide range of the possible
mushroom-forming species found in nature.
In the order Agaricales, most of the gilled mushrooms include species like Amanita muscaria,
the fly Agaric, and the white button mushroom, Agaricus bisporus.
In this tutorial, we will be discussing gilled mushrooms from the following families: Inocybeaceae,
Strophariaceae, and Hymenogastraceae.
First, we will discuss the genus Inocybe, which have their own family, Inocybeaceae.
Inocybe is a large genus consisting of thousands of different species of small brown, gray,
or yellowish mushrooms with some purple exceptions.
Generally, these mushrooms require microscopy of spores and cystidia to identify to the
species level, so we will focus on the general characteristics of the entire genus.
The Greek root “ino” from inocybe means fibrous, which references the lacerated or
fibrous pattern that appears on many of the species’ caps.
The caps are conical, often having a pronounced central umbo.
Many of the species have a noticeable odor, ranging from sweet and fruity to smelling
unpleasantly fishy.
In addition to producing repulsive odors, most Inocybes are poisonous.
They contain a toxin called muscarine which can lead to death at certain amounts.
Next let’s discuss the family Strophariaceae.
These are gilled mushrooms that produce red-brown to dark-brown spores.
Under a microscope the spores have a glabrous, or smooth surface with an apical germ pore.
The gills are attached to the stipe.
The Greek root “stroph” means belt, which indicates the presence of a partial veil on
many species in Strophariaceae.
These mushrooms form in clusters and are saprobic, meaning they feed on dead organic matter like
leaf litter or decaying wood.
We will discuss important species from three genera in the family Strophariceae: Stropharia,
Hypholoma, and Pholiota.
Stropharia rugosoannulata, the King Stropharia, or the Wine Cap, is a large edible mushroom
that is usually found breaking down woodchips.
So this fungus is relatively easy to cultivate for consumption.
It has a wine red cap color when young that fades to yellow-beige when old.
The gills transition from pale gray to purplish gray as they age and produce a purple-brown
spore print.
The stipe is white to yellow-white.
The species name rugosoannulata is derived from two latin roots: rugos, meaning wrinkly,
and annulus, which means ring.
So this species has a wrinkly partial veil.
Historically, Stropharia rugosoannulata was cultivated alongside corn to enhance the soil
nutrient composition and growing conditions.
The hyphae of this species have specialized cells that can kill nematodes, which are microscopic
worms.
The next species, Hypholoma fasciculare, the sulfur tuft mushroom, is a fungus that forms
tightly packed clusters on decaying wood.
The genus name hypholoma originates from the greek root “hyph”, meaning thread.
This references the thread-like remnants of the partial veil that are on the margin of
the cap.
The species epithet is fasciculare, which is derived from the latin root fascia which
means bundles, and describes the clusters that sulfur tufts form.
If you were to take a small bite out of the cap and spit it out, it would have an intensely
bitter taste.
If you were to instead swallow a substantial amount of the mushrooms, you would have severe
nausea, vomiting, and diarrhea.
The gills produce a purplish-brown spore print, and the gill color is yellow, turning darker
as they age.
Sulfur tufts are widely distributed around the world but are notably found in England
and the west coast of North America.
Next, let’s discuss mushrooms in the genus Pholiota, which gets its namesake from the
Greek root “phol” which means scale.
The type species, meaning the species that mycologists have chosen to represent a genus,
is Pholiota squarrosa, or the shaggy scalycap.
The mushroom received this name because both the cap and stipe of the mushroom are covered
with pointed scales.
The mushroom is saprobic and is an opportunistic parasite among a diverse number of trees.
An opportunistic parasite can only infect a tree when it is already weakened by a previous
infection from bacteria or other fungi.
All pholiota species are considered white rot fungi, which describes fungi that only
break down the lignin of wood, leaving the white fibrous cellulose.
Another type of wood decay is brown rot, which breaks down the cellulose, leaving only crumbly
brown lignin.
Pholiota squarrosa can produce combinations of smells of garlic, radish, and lemon.
Another important species of Pholiota is Pholiota microspora, or the nameko mushroom.
Widely cultivated in Japan, Nameko has a delicious nutty flavor and a gelatinous layer on the
cap that acts as a thickening agent for stir-fries or miso soup.
The mushroom is suspected to have medicinal benefits as well.
Now that we have covered some of the diversity in the family Strophariaceae, let’s move
on to a genetically similar family, Hymenogastraceae.
Originally, this family only housed species of false-truffles from the genus Hymenogaster.
However, since the addition of genetic analysis, some infamous gilled mushrooms have been moved
to this family.
We will discuss two important genera in Hymenogastraceae: Galerina and Psilocybe.
Lets begin with the genus, Galerina.
All Galerina species are saprobic, but many species are found in association with mosses.
The caps of these mushrooms are typically brown, glabrous, and hygrophanous.
The gills will be attached and produce variable brown spore prints.
The spores of many Galerina species have a distinct feature where a part of the outer
covering is incomplete leaving a clear patch called a plage.
The most infamous species of Galerina is Galerina marginata, or the deadly galerina.
This little brown mushroom grows in clusters on wood.
It contains amatoxins, which in very small doses, cause extreme liver and kidney damage.
Generally, poisonings from this species occur after mistaking the mushroom for a species
from the genus Psilocybe.
This genus, commonly known as “magic mushrooms”, is an iconic group of gilled mushrooms famous
for their hallucinogenic properties.
Psilocybe species are similar to Galerina species as they are generally small and brown,
with a hygrophanous cap and produce variable brown spore prints.
This genus is found throughout the world in a variety of habitats and is saprobic on a
number of different substrates.
A key identifying characteristic is a blue-staining reaction when the fruiting body is bruised.
This staining is caused by the oxidation of a molecule called psilocybin.
This molecule gets broken down into a similar molecule called psilocin, which is the source
of the hallucinogenic properties of these mushrooms.
Psilocybin is the subject of much research in the field of ethnomycology, which studies
historical uses and sociological impacts of fungi.
Psilocybin is also beginning to generate research for its potential use as a therapy for anxiety
and depressive psychological disorders.
Let’s now move on to some other areas of the order Agaricales.