A mushroom is a saprophytic plant, considered a fruit for purposes of heraldic classification. It’s a period charge, found in the arms of Dryland, c.1480 [DBA2 351], and the arms of Phoffwintzer, mid-16th C [NW 65]. The mushroom is couped by default; occasionally, the type (e.g., “morel”) is specified in blazon.
Deborah the Wanderer bears: Purpure, a mushroom argent.
Leopold van Audenhoelve bears: Sable, three mushrooms argent.
Geoffrey des Champignons bears: Or semy of mushrooms, a bordure sable