What is a “deer mushroom”?

Show anyone you meet out hiking a fairly nondescript brownish-grey mushroom and they’ll probably tell you it’s a “deer mushroom.” But what actually is a deer mushroom, other than a catch-all term for things we can’t otherwise identify?

It’s actually fairly simple. A deer mushroom (Pluteus cervinus) has three key characteristics: 1) it’s growing from decaying wood 2) the gills don’t touch the stem, and 3) the gills turn pinkish with age, and drop a pinkish spore print. Keep in mind though, that what mycologists call “pink” isn’t what most people call pink. Look for a reddish brown or dark salmon color.

You might be wondering why it’s called a deer mushroom. Do deer eat it, or is it from the brownish-grey color of the cap? In fact, the name comes from a microscopic antler-like feature of the pleurocystidia (I’m not sure what exactly that is either).

A final note: not everything people call a deer mushroom is a deer mushroom. Several species of Entoloma mushrooms (some of which are toxic) look quite similar, at least judging from the cap. Entoloma sinuatum, which is responsible for about 10% of mushroom poisonings in Europe, also has pink gills and a brown cap. The key difference is that Entoloma mushrooms grow from the ground, not decaying wood, and that their gills touch the stem.