Cyclocybe aegerita or agrocybe aegerita, a mushroom with a tan or brown top and slender cream-coloured stalk that grows out of the stumps of poplars (pioppi) or chestnut trees a
They are widely cultivated in Italy (the Roman writer Pliny mentioned it). They are often dried, and are popular in a pasta sauce.
Also known as piopparelli.
Image by Ramiro Barreiro, GNU documentation license