Collection location: Albion, Mendocino Co., California, USA [Click for map]
This was id’ed with the help of Dr. Desjardin, in his bio 800 course.
He took ammonia hydroxide (I think?), and didn’t even touch the cap, but brushed it close over the cap. The cap quickly stained a blue-green color. Over the course of an hour, the blue-green slowly faded to grey. This is a feature of this species.
The species also seem to have the look of B. subtomentosus, but with a more fibrilose redish cap. Dr. Desjardin mentioned to me that there are suggestions from initial dna studies, that actually these are the same species, and the redish caps and reactions to ammonia are just variations.
But this isn’t final or published yet (I think?), so this is listed as a separate species from Theirs’ Boletes of CA.