IT’S DIFFICULT TO TURN A CORNER ANYMORE and not see the white and red image of a Fly Agaric mushroom emblazoned on hats, scarves, shirts, earrings and even on the skin as tattoos. The irony is that the Fly Agaric — the red-capped, white-speckled amanita mushroom (Amanita muscaria) of fairy tales, is poisonous. The iconic mushroom has been associated with shamans and the rituals of the Koryak people of northeastern Siberia, who use it to create trance-like lucid-dreaming states. In their rituals, the shamans feed the mushroom to reindeer and then collect the animals’ urine and drink it to induce…