Decurrens had a definite stalk while these two did not the one I found on the ground might vary well have been tuberaster but I’m betting these are gayanus. LOL Gay anus!

I would never be able to find the exact spot in order to find the tuber. I’ll look out for it if I see this again. So far I’ve found three of these two were on wood one was on the ground and they were all under different trees all calif. live oak just different ones.

Maybe there is a tuber down there.
Check out Polyporus tuberaster to see if it matches.
http://mushroomobserver.org/name/show_name/107
You might have to dig up the tuber!

Since the fair I found this species again on the ground growing from buried wood. It did have a stem in this case much younger specimin. I also took a bite tasted fairly good kind of a nutty flavor.