Probably Paxillus involutus

Tylan said: Found this growing all around the bottom perimeter of an old growth conifer stump. Smells real bad. Spores dark brown. Cap viscid.
What is it?

Judy said:
Are you sure that was a conifer stump? That mushroom sure looks like Paxillus involutus, a birch associate. Arora says it does associate with pine and oak as well, but have not encountered it that way.
The decurrent gills with a like waviness to them, the brown staining and viscid, slightly incurved margin point to this mushroom.
BTW, this is related to boletes and you can peel the gills right off the flesh and leave it disturbed. That is another identifying character, as most gilled mushrooms don't exhibit this feature.

Tylan said
I suppose it could be a very large birch stump from old times. And yes, it has all the other characteristics you mentioned. I just peeled off the gills just like a bolete!! It is drying pretty nice too.
Arora says Paxillus involutus grows on ground, which is why I had eliminated initially. But it is apparently possible that a well decaying stump could be considered as ground in some cases.

Judy said:
That's true that the stump is very well rotted.
Because the gills peel and leave a smooth surface below them, that cinches it. Few other mushrooms have that feature. If you had a microscope, you could see that the spores are also shaped similarly to those of boletes.