Cap surface

Smooth

A smooth, bare (glabrous) cap surface is the basic "factory setting" in the fungal kingdom. It means there are no decorations at all: the cap has no scales, no fuzz (velvetiness), no slime and no radial fibers. The skin is even, often with a slight matte or satiny sheen.

This is the most common trait in the forest, and that's exactly why it tells you the least when it comes to pinning down a mushroom's identity.

24 species in the database.

Smooth champions

According to David Arora and Roger Phillips, hundreds of species have a smooth surface. Among the best known:

1. Brittlegills (Russula): Most green, yellow, red and purple brittlegills have perfectly smooth skin that you can often peel back with your fingers halfway across the cap.

2. Agaricus mushrooms (Agaricus): The classic wood and field mushrooms (when young) have a completely smooth, white, silky cap (though some species may develop barely visible scales with age).

3. Chanterelle (Cantharellus cibarius): Its yellow cap always stays dry and smooth.

4. Death cap (Amanita phalloides): The deadly danger is that the death cap (unlike other amanitas) almost never has white spots on its cap. Its olive-green skin is perfectly smooth, sometimes with a silky sheen, which makes it incredibly similar to a smooth green brittlegill.

The problem of "balding" mushrooms

M.Ya. Zerova warns foragers again and again: many smooth mushrooms aren't actually smooth by nature.

For example, the fly agaric in its classic form has a cap with white warts. But these warts are crumbly remnants of the universal veil. If it has rained hard for a few days, or the mushroom has rubbed against grass, it "goes bald" completely and becomes perfectly smooth.

Old scaly mushrooms can turn smooth the same way (the scales simply wash off or fall away).

Questions and answers

If the cap is smooth, does that mean the mushroom is safe?

Absolutely not. A smooth cap is a feature of excellent edible brittlegills and Agaricus mushrooms, but also of the deadly poisonous death cap and destroying angel, as well as the poisonous spring pinkgill. If the cap has no distinctive features (slime or scales), you need to use other markers to identify it: the presence of a ring, a volva (sac) and the color of the gills.

How do you tell a smooth cap from a slimy one if the mushroom is wet after rain?

When it rains, ANY mushroom (even a dry, smooth one) will be wet and may seem slimy. A truly slimy (sticky) cap, like a slippery jack's, is coated in a thick layer of gelatinous slime that stretches after your fingers. On a smooth mushroom, rainwater simply runs off the skin (it's wet, but not sticky).

Sources

1.Зерова М.Я. та ін. Визначник грибів України. 1979
2.Roger Phillips. Mushrooms (Roger Phillips)
3.David Arora. Mushrooms Demystified
4.Index Fungorum