Jews and mushrooms have not always had a happy association. During medieval times mushrooms had extremely unpleasant connotations. Antisemitism was rife, so when a fungus that looked like a thick rubbery fleshy ear was discovered, it was immediately labelled as a Jew's Ear or Judas's Ear fungus. Its official Latin name was auricularia auricular Judea. It grew on an elder tree - from which Judas was believed to have hanged himself - so a myth was established that linked this fungus with the story of Judas's betrayal.
Equally unpleasant was the description of all mushrooms as "Jew's Meat". They were considered slimy and disgusting and often poisonous so were rarely used as food unless people were starving.
It may seem surprising that Jews should have been associated with such an ugly and potentially dangerous food, but to medieval people, Jews were alien. They were a strange group of people who did not conform to their mode of life. In the same way as the Jew seemed to appear from nowhere, dressed in a different garb and looking extraordinary, so a mushroom materialised suddenly, as if by magic,
In 1938, the toadstool/Jew myth was further expanded by the publication of a child's storybook intended as antisemitic propaganda called Der Giftpilz (literally "the toadstool" or "poison mushroom") with caricatures of Jews in the shape of toadstools.
