Bondarzewia berkeleyi is a large, centrally stalked poroid mushroom. Commonly known as Berkeley’s polypore, this species usually has multiple fleshy caps that form overlapping clusters and attach to a single stalk. Individual caps are generally convex and bear a decurrent poroid surface. At maturity, the fruiting body can reach 80 cm across (Kuo 2004). This mushroom is annual, arises from a sclerotium, and can be found June-October.
This is more typical of what I have seen: