Most mushrooms are fragile things, seldom lasting in the wild more than a few days before decaying. So the discovery of this 94-million- year-old mushroom encased in amber delighted David Hibbett, a mycologist at Harvard. To find one preserved at all and to find it preserved so beautifully and to have it be so old is just unreal, he says. Amateur collectors found the fossil in East Brunswick, New Jersey, and passed their find on to David Grimaldi, an entomologist at the American Museum of Natural History in New York, who then turned to Hibbett to help classify it. The gilled mushroom, complete with a stalk and a .1-inch-wide cap, is at least 50 million years older than any known fossil mushroom, says Hibbett. While it was alive, resin from a tree of the cedar family covered the mushroom and preserved it. The ancient mushroom’s strong resemblance to a living fungus called Marasmius hints that evolution has conserved the basic form of this mushroom for a very long time indeed and has led Hibbett to consider naming the fossil Archaeomarasmius. If you found this growing out in the woods now, says Hibbett, you wouldn’t bat an eye, because it’s absolutely typical.