Field guides, a hand lens and the three-feature rule
April 5, 2025 · 3 min read
The method I settled on in my first winter, when there was nothing to pick and plenty of time to read, is a simple one: before anything is eaten, at least three independent features have to agree with the description in two different field guides, and nothing in either book’s list of lookalikes can be left unchecked. Independent means features that do not depend on each other. Cap colour and cap size are one feature as far as I am concerned, because both vary with age and weather. Spore print colour, how the gills attach to the stem, whether the flesh changes colour when cut, the smell, the habitat and the season are the kind of things that count.
The kit for this is small and lives in a canvas shoulder bag by the back door:
- A short knife with a brush on the handle, for cutting and cleaning.
- Paper bags, one per species, so nothing gets mixed and nothing sweats the way it does in plastic.
- A hand lens, ten times magnification, which has shown me ring remnants and gill edges I would never have seen with the naked eye.
- A pencil and a small notebook that gets wet and dries out again.
The notebook is where the discipline actually lives. For every specimen that comes home I write the tree species it was under or on, the ground (grass, leaf litter, moss, bare soil, wood), how it was growing (alone, in a group, in a ring, in tiers), the date, and then the features one by one with a tick or a cross against each book. I dig up the entire base with the knife rather than cutting the stem, because a sac or a bulb at the bottom is one of the most important things to see and the easiest to leave behind in the ground.
The other thing I did that winter was join a local walk led by someone who has been doing this for decades. What struck me most was how often that person said “I don’t know” about a specimen, turned it over, smelt it, and put it back. If that is what forty years of experience sounds like, then a beginner with two books and a hand lens has no business sounding more certain. I have borrowed the phrase and use it often.
None of this makes me an expert. It makes me a careful beginner, which is the only kind I want to be.