Concave

True funnels (shaped from birth)

For some families, a concave shape is a defining feature at every stage of life (even when young):

1. Chanterelle (Cantharellus cibarius): The absolute benchmark. Its yellow fruiting body widens smoothly from the stem into a deep, concave "funnel" with wavy margins.

2. The milk cap family (Lactarius): Saffron milk caps, black and white milk caps, woolly milk caps. Their cap always has a characteristic deep dip in the center. When it rains, a "puddle" of water with forest debris often collects in this dip. (The acrid milk caps, such as milk caps and woolly milk caps, are conditionally edible: they are soaked and salted; saffron milk caps don't need this).

3. Horn of plenty (Craterellus cornucopioides): This delicacy (often dried) is shaped like a deep, black, hollow tube or flared trumpet (a horn shape).

Funnels from old age

For many other mushrooms, a concave shape is the final stage of aging.

As M.Ya. Zerova notes, when a convex mushroom opens up to release its spores, it first becomes flat. But if it keeps living and drying out (or soaks up too much water), its margins start curling even higher (upward), and the cap turns into a funnel.

- Brittlegills (Russula): Old brittlegills almost always become concave like a saucer, and water collects in their center. At this stage their flesh turns tasteless and crumbly.

- Honey fungus and Tricholoma (knights): These also often turn their margins up in deep old age.