Also called grey knight tricholoma, dirty tricholoma is found growing in troops during the autumn on calcareous soil under conifers especially pine and spruce in Europe and North America. It grows in needle debris and blends in with the soil. The mushroom grows up to four inches tall and has a cap 1 ½ to 2 ¼ inches wide. The shape of the cap has been likened to that of a coolie hat with a cental umbo and smooth margins. The cap is dark gray, dry, thin, and covered with fine gray scales. The widely spaced gills are free, unequal in size, sinuate, notched, and white turning dirty brown with maturity. The sturdy stem is ¾ to 2 inches long, white turnning gray, and lacks a ring and volva. The spores are white.
Although traditionally considered edible and widely sold in markets in Europe, recent evidence suggests that it may contain toxins that cause the rapid breakdown of skeletal muscles. The flesh has a mild fragrance and flavor but is very thin and tears easily. Dirty tricholoma can be sautéed in butter or oil along with onions, garlic and peppers for use with pasta, rice, polenta, meat and fish.
There are many species of Tricholoma that are edible but some that are poisonous so be sure to seek the advice of an expert when collecting the in the wild for the table.