The Gills Lied About Their Colour

Dear version of me who hasn’t tried this yet,

You’re going to crouch down in a poplar stand somewhere north of the city with a field guide in one hand and absolutely no idea what you’re looking at. The cap will be brownish. The gills will be brownish. The stipe will be brownish. You’ll flip through pages of nearly identical illustrations and wonder how anyone ever learned to do this.

That moment of bafflement is the point. Stay with it.

Mycologists have a term for what you’re staring at: LBM. Little Brown Mushroom. It’s a confession dressed as an acronym — thousands of species that experts can’t reliably distinguish in the field without microscopy. There’s also BUM (Boring Ubiquitous Mushroom) and JAR (Just Another Russula). The taxonomy has jokes baked in. Nobody pretends this is easy.

You’re going to bring one home anyway. You’ll place the cap gill-side down on a sheet of paper that’s half white, half black — the dual background matters, because some spore prints are so pale they only show against dark paper, and some are so dark they only show against light. Cover it with a glass. Walk away. Check back in six hours.

This is the part that should sound familiar. When you were mixing mugi urushi for the kintsugi repair, waiting days for lacquer to cure in a cardboard humidity chamber, you learned that some processes demand you leave. The mushroom won’t produce a print while you watch. Neither will fermentation, or polymerization, or grief. You create conditions, then you step back, then you discover what happened in your absence.

The print under the glass will probably surprise you. Gill colour lies. This is the first hard lesson: you cannot look at the underside of a mushroom and guess what colour the spores will deposit. A young specimen with white gills might drop a rust-coloured print. A mature one with dark gills might drop white. You have to run the experiment.

Elias Magnus Fries was a Swedish botanist who died in 1878, and modern mushroom taxonomy still rests on his framework. His organizing principle: spore print colour is the primary key. White spores, pink spores, brown spores, purple-black, rust. Entire families sorted by what falls out when the cap sits on paper overnight. He described over three thousand species in his career. You will identify maybe three this year, and one of them will be wrong.

Take the wrong one seriously. The genus Amanita is responsible for ninety percent of mushroom poisoning deaths worldwide. The toxin — α-amanitin — is patient. Symptoms don’t appear for six to twelve hours, by which time the liver damage is done. A mushroom that doesn’t make you sick immediately is not a mushroom that’s safe to eat. Never eat anything you cannot identify with absolute certainty, and then identify it again.

What drew me here wasn’t the danger, though. It was the network.

You’ve spent time thinking about distributed systems. You’ve watched the waggle dance diagrams and marvelled at bees encoding navigation data in figure-eights. Now look down. Beneath the poplar stand, beneath every tree in the boreal forest, ectomycorrhizal fungi thread between root cells — not penetrating them, just wrapping around, trading sugars for phosphorus, water, nitrogen. The mycelium connects trees to trees. Not metaphorically. Physically. A Douglas fir injured by bark beetles can send chemical signals through the fungal network, and a neighbouring ponderosa will start producing defence enzymes. Nobody fully understands how. Suzanne Simard at UBC has been mapping these connections since 1997. The science is younger than most of your houseplants.

The mushroom you’re holding is a fruiting body — the reproductive structure, not the organism. The organism is the mycelium, and the mycelium might span acres. You are picking a single flower from something forest-sized and mostly invisible. The thing you’re trying to identify is also the smallest visible part of the thing you’re trying to understand.

Edmonton sits at the edge of boreal and aspen parkland. The mushroom season runs roughly July through September, peaking after rains. You have months to read David Arora and practice your spore prints on grocery store specimens before you need to make any decisions in the field. Use them.

One last thing. You’re going to get frustrated by how slow the learning is. Debugging teaches you to isolate variables, run tests, confirm hypotheses. Chess teaches you to recognize patterns you’ve seen before. This is different. The patterns don’t repeat cleanly. The variables — weather, substrate, age, species variation — are entangled in ways you won’t map quickly. Some days you’ll come home with nothing but photographs and confusion.

Those days count. They’re what the fingers are doing while the brain catches up.

Trust the print. Trust the wait.