According to the key on pg. 47 of "California Mushrooms: The Comprehensive Identification Guide" distinguishing Lactarius from Russula depends on whether the fruitbodies do or do not (resp.) exude latex (white, orange, or red) when cut across the gills. I can't see evidence of exudate in my photos, and we didn't check by making a small "slice" in the field.
Some companions on our walk opined this was Lactarius deliciosus, and iNat's automatic ID matching algorithm also suggested the same. But the description of L. deliciosus in "California Mushrooms" states the cap of is "convex to plano-convex" and is illustrated as substantially gray...whereas the cap here appears appreciably "concave-up" (umbella-like) and all brownish-orange (or "br-orange"? ;-).
So I'm just placing to Lactarius for now.