I got a call one day from a lady who claimed she had a 'mushroom' more than three feet across growing under and oak tree in her garden. So next day I jumped in the car and took off with her instructions on how to find her country home on RR # something or other! It took me more than an hour of driving from Guelph before I found her place. After we had settled down a couple of rambunctious dogs of nonspecific ancestry the lady showed me this marvelous fungus photographed above. I can't remember the exact measurement but it was close to 100 cm at its widest although the average was less than this. I had never seen the mushroom before but with a little help from my friend (Scott Redhead) it proved to be Bondarzewia (apparently pronounced bon dar zevia). I sent al the particulars to Scott and it may well be a Canadian record for this species. Bondarzevia berkeleyi causes butt rot of hardwoods
Fruitbodies are 25-90 cm across and up to 30 cm tall, with one, several or many caps arising from a single root-like base. Caps are pale buff to tan or greyish brown, spongy tough, with a radially roughened surface. Pore surface is whitish with circular to angular or sometimes labyrinthiform pores. If cut when fresh it exudes latex. Widespread but not common, this unusual bracket fungus causes butt rot of standing trees and fruits on the ground close to the trunks of living hardwoods particularly oak.