Jew's ear

 

noun

  • a common fungus with a brown rubbery cup-shaped fruiting body, growing on dead or dying trees in both Eurasia and North America.
    • Auricularia auricula-judae, family Auriculariaceae, class Hymenomycetes

Origin:

mid 16th century: a mistranslation of medieval Latin auricula Judae 'Judas's ear', from its shape, and because it grows on the elder, which was said to be the tree from which Judas Iscariot hanged himself