How to Change Your Mind

the practice of mulching with wood chips has vastly expanded the range
of a handful of potent Psilocybes once confined to the Pacific Northwest.
They now thrive in all those places we humans now “landscape”:
suburban gardens, nurseries, city parks, churchyards, highway rest stops,
prisons, college campuses, even, as Stamets likes to point out, on the
grounds of courthouses and police stations. “Psilocybe mushrooms and
civilization continue to co-evolve,” Stamets writes.
So you would think these mushrooms would be fairly easy to find. In
fact after I published an article about psilocybin research, I was informed
by a student that after the December rains Psilocybes can be found on the
Berkeley campus, where I teach. “Look in the wood chips,” he advised.
Yet as soon as I began studying the photographs in Stamets’s field guide,
I began to despair of ever identifying any mushroom as a member of the
genus, much less learning how to distinguish one species of Psilocybe
from another.
To judge from the pictures, the genus is just a big bunch of little brown
mushrooms, most of them utterly nondescript. By comparison, the edible
species with which I was familiar were as distinct as tulips are from roses,
poodles from Great Danes. Yes, all the Psilocybes have gills, but that isn’t
much help, because thousands of other mushrooms have gills, too. After
that, you’re trying to sort out a bewildering array of characteristics, not all
of which are shared by the class. Some Psilocybes have a little nipple-like
knob or protrusion on top—it’s called an umbo, I learned; others don’t.
Some were “viscid”—slippery or slimy when wet, giving them a shiny
appearance. Others were dull and matte gray; some, like azurescens,
were a milky caramel color. Many but not all Psilocybes sport a
“pellicle”—a condom-like layer of gelatinous material covering the cap
that can be peeled off. My fungal vocabulary might be expanding, but my
confidence was rapidly collapsing, much like the mushroom that, in the
course of a single day, decomposes into an inky puddle.
By the time I got to chapter four, “The Dangers of Mistaken
Identification,” I was ready to throw in the towel. “Mistakes in mushroom
identification can be lethal,” Stamets begins, before displaying a
photograph in which a Psilocybe stuntzii is seen growing cheek by jowl
with a trio of indistinguishable Galerina autumnalis, an unremarkable
little mushroom that, when eaten, “can result in an agonizing death.”