Posted on WhatIsThisMushroom by Paul Whitney 12/30/14
It is Pluteus. Grows on wood, and saw dust qualifies.
It's a great genus to practice microscopy.
It usually has easy-to-find cheilocystidia and pleurocystidia,
and a variety of structure on the cap surface.
Great to observe clamp connections as well:
if you section a little scalp of the "deer mushroom" you find,
the chances are that there
will be tons of conspicuous clamp connections there.
Which, by the way, will prove that your
find is not Pluteus cervinus, even though that's the name typically applied.
The most common Pluteus species in the PNW is probably P. pouzarinus (which grows on conifers and has clamps on cup surface).