 Ethnobotanical and ethnomycological scholars such as R. Gordon Wasson, Carl Ruck and Clark Heinrich write that the mythological apple is a symbolic substitution for the entheogenic Amanita muscaria (or fly agaric) mushroom.Its association with knowledge is an allusion to the revelatory states described by some shamans and users of psychedelic mushrooms.At times artists would co-opt the apple, as well as other religious symbology, whether for ironic effect or as a stock element of symbolic vocabulary.