Very good info and photos. I agree that these are likely the same species as the ones down near Santa Cruz growing with Arbutus menziesii… Whatever species that is.
And yeah, the colour is not quite brown, not black, grey, red, nor blonde. Too variable.
Nice dog. Is she a blue heeler or AU shepherd? Or a cross? My roomate has a heeler/pit mix that I have tried to take mushroom hunting, but every time I call her over to look at a mushroom, she skulks away. Then if I bring the mushroom to her to check out, she turns her head away with this pained expression on her face, haha. She totally loves walking on the mushrooms while I am trying to photograph them, though.
So good work and lucky you for getting your dog to get it on the mushroom action.