Tricholomataceae: Knights, Matsutake and Wood Blewit

The Knights and the Smell Test

Five of the seven members are Tricholoma, the genus of the knights. All five have white spores and grow in partnership with tree roots. Smell separates two of them. Matsutake earns its price with a strong spicy cinnamon and pine scent, while Sulphur Knight gives itself away with a strong smell of coal gas or tar. Neither smell survives a photograph.

Your photo of a yellow mushroom cannot separate the sulphur knight from the Yellow Knight, because the camera has thrown away the character that tells them apart. Burnt Knight is a brown, wet-sticky knight of beech woods whose pale notched gills develop brown spots. Related poisonous brown knights in Asia and North America need their own regional names.

Tiger Knight is the heavy gray member, with a dry pale gray cap spotted with darker scales, broad notched white gills and a mealy smell. Several gray knights share parts of that look, so you need the whole set of traits plus the regional habitat to name it. It can cause a severe gastrointestinal irritant syndrome, and no verified household preparation makes it safe to eat.

Why Is the Yellow Knight Avoided?

Some traditions eat the yellow knight. Yet twelve French patients developed delayed rhabdomyolysis, a breakdown of muscle tissue, after repeated meals blamed on it. Three of them died. Nobody has established a toxic dose or a tolerable dose, and France bans its trade and distribution.

The Confusions That Cause Harm

The dangerous confusions for the two edible members come from outside the family. Matsutake shares Pacific Northwest pine ground with Amanita smithiana, a whitish mushroom with no spicy smell that causes kidney failure days after the meal. So the scent you buy matsutake for is also its first safety check.

Wood Blewit shares its lilac color with many webcaps. Several webcaps contain orellanine, which damages the kidneys so slowly that people may not link the illness to the meal. The blewit's bare stem, with no cobweb veil, and its pale pinkish buff print separate it from a webcap's rusty brown print. Even a correctly named wood blewit needs thorough cooking, and it still disagrees with some people.

Fool's Funnel is the family's lawn species, a small whitish muscarine mushroom that can fruit in rings. Fairy ring mushroom has a smooth tan cap, widely spaced gills and a tough wiry stem, while fool's funnel is softer, paler and more crowded beneath. Both can form rings on grass, so the ring itself tells you nothing.