At this point we have already examined a number of mushrooms, and discussed important aspects
of their morphology.
As we continue to learn more about mushrooms, we will eventually become able to identify
specific species of mushroom in the wild, and this is one of the primary goals of our
study of mycology.
So to better serve that goal, let’s go through a survey of terminology that will be tremendously
useful in recognizing and identifying mushroom species.
Naturally, all fungi have physical characteristics that can assist in accurate identification,
and we have discussed a handful of these characteristics already.
As we know, mushrooms are actually the fruiting body, or spore-producing structure of the
fungus.
Luckily, among all of the different species of fungi, fruiting bodies have an enormous
diversity in physical traits.
Traits that we can see with the naked eye are called macroscopic features.
They include shape, size, color, texture, and surface structures.
Many mushrooms that we will discuss in this series have a cap and a stipe, and they vary
greatly in the structure of their hymenophore, or spore-producing structure.
The hymenophore may be smooth, ridged, tooth-like, or porous.
The caps of different mushrooms also have a number of descriptive terms including plane,
convex, cylindric, conical, cuspidate, and infundibuliform.
These caps can have different textures and colors.
If the cap color fades as the mushroom ages, it is termed hygrophanous.
The cap is glabrous if its surface lacks any texture and is smooth to the touch, pubescent
if its surface is fuzzy, squamous if it has scales, and glutinous if it is slimy.
Many mushrooms also have a wrinkled or rugulose cap.
We have already discussed the gilled hymenophore in Amanita jacksonii and Amanita muscaria.
Among the many other gilled mushrooms, the shape and structure of gills can vary.
These gills can be thick or thin.
Some gills may be distant or crowded.
Gills do not always connect to the stipe.
We call these free gills.
The term breadth is the distance from the cap to the free edge of the gill.
If the gills are connected to the stipe, they may have a structure that is adnexed, adnate,
emarginate, decurrent, or collared.
Adnex gills connect at the top of the stipe at an angle and curve outward.
Adnate gills connect to the stipe at around a 90 degree angle and have little curvature.
Emarginate gills connect to the stipe at an angle, curve inward, and then curve outward.
Decurrent gills connect low on the stipe at an angle and curve inward.
Collared gills do not connect to the stipe but form a collar that surrounds it.
The stipe of a mushroom can be solid or hollow.
Stipes may have a partial veil with a variety of textures from slimly to threadlike.
Flaring veils attach and flare upwards.
Pendant veils flare or hang downwards.
Cortinate veils form a web-like mesh that covers the gills.
Sometimes there may only be a ring zone that shows the remnants of a veil.
And often mushrooms show no signs of a partial veil.
There are also features that are unique to certain mushrooms.
Some mushrooms secrete a milky liquid called a latex when part of the fruiting body is
cut or broken.
Some change color when exposed to air.
Many mushrooms change color when placed in contact with a solution of potassium hydroxide.
Smell and taste are also important factors in mushroom identification.
From the pungent edible truffles to the smell of green mold on bread, fungi can produce
a wide array of unique smells.
The classic mushroom scent comes from the commercially produced button mushroom.
Other mushroom scents include radish, chlorine, almond, decaying flesh, banana, honey, hot
metal, and apple cider.
However, people may perceive these scents quite differently, so you can only experience
them yourself by finding and sniffing as many mushrooms as possible.
When tasting a mushroom, mycologists will generally take a small bite from the pileus
or cap of the mushroom.
They will chew it for about ten seconds to release the flavors, then spit it out.
When tasting mushrooms, it is important to first rule out any notable poisonous mushrooms.
Common tastes include mild, spicy, very spicy, bitter, peppery, and sour.
Spore color is also a useful tool that does not require microscopy.
In order to see the spore color, mycologists will make a spore print by placing a fungus
with its hymenium on a surface such as printer paper, aluminum foil, or wax paper.
After a few hours, the spores from the mushroom will fall on to the paper and produce a spore
print, displaying the spore color.
In general, these macroscopic features are quite useful when identifying species of mushrooms.
However, many mushrooms require the analysis of microscopic features such as spores traits,
basidia, and other cell and tissue types.
Microscopic analysis requires the use of a microscope with about one hundred times magnification.
The key microscopic characteristic for mushroom identification is spore morphology, or the
structure of spores.
When looking at spores under a microscope, you generally add a droplet of water to a
spore print and pipette the spore solution on a microscope slide to be able to look at
it under a microscope.
The first feature to notice is the size of the spores.
Size will range from about 3 micrometers to over a hundred.
Spores are diverse in their shape, being spherical, lemon-shaped, thread-like, disc-shaped, and
many others.
Mycologists must work to measure the length and width of spores that are not spherical.
The spore surface can also have different textures.
If the surface is smooth, it is termed glabrous.
Spore texture can also be described as warty, spiny, angled, or veined.
Some spores will change color in the presence of certain chemicals.
A notable combination of chemicals is called Melzer’s reagent.
If spores turn blue in the presence of Melzer’s reagent they are amyloid.
If they turn reddish-brown they are termed dextrinoid.
Other than the spores themselves, mushrooms have unique microscopic features associated
with different tissue types.
Along the hymenium, basidiomycetes possess spore-producing cells called basidia.
These can belong to a number of structural types.
Generally, basidia produce four spores but notable species and fungal lineages produce
two spores per basidium.
Finally, along different tissue types there are cells which are unrelated to spore production
called cystidia.
Cystidia are categorized as different types depending on their location on the fruiting
body.
They are called caulocystidia if on the stem, pileocystidia if on the cap, cheilocystidia
if on the gill edge, and pleurocystidia if on the gill sides.
Mushrooms will exhibit variation in the size and structure of each type.
So mycologists can use this variation in each of these microscopic features to ensure taxonomic
classification.
And with that we’ve covered a substantial list of terminology associated with the structural
features of mushrooms which we will continue to refer to as we move forward with this series,
and will be of tremendous use to anyone who wishes to identify mushrooms
in
the wild.