(Fistulina hepatica), also liver fungus, a fungus of the group Polyporaceae. Beefsteak fungus grows on old trunks and stumps of hardwood trees, predominantly oaks. The fruiting body is tongue shaped and attaches itself to the trunk by the edge of its cap or by a short, secondary stem. When young, the fungus is fleshy and blood-red, becoming faded and hard with age. Beefsteak fungus is mainly distributed in the central and southern zones of the USSR.