Bondarzewia berkeleyi, commonly known as Berkeley's polypore, or stump blossoms, is a species of polypore fungus in the family Russulaceae. It is a parasitic species that causes butt rot in oaks and other hardwood trees. Although Bondarzewia berkeleyi is edible, it has been compared to eating shoe leather.
The fan- or shelf-shaped caps grow in overlapping clumps from the bases of oak trees, each capable of growing to 25.5 cm diameter. They are various shades of white to pale grey, cream, beige or yellow. The pore surface is white, as is the spore print. The outer edges that cut easily with a knife are quite tender.
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