First of all it is certain, that the original (european) B. regius does not stain blue at all. It is a very very VERY rare exception that you can find one out of thousand fruitbodies were you may detect a slight blue reaction at a scratch, but never a complete bluing of the pores e.g.. Those bluing “regius” are called B. speciosus in America and B. pseudoregius (syn. B. fuscoroseus) in Europe. The european type material of pseudoregius and the american type material of speciosus are not identical and show e.g. differences ind the spore size, especially in the width of the spores.
What concerns the non-blueing regius, I’m not sure whether the american non-blueing regius has a name already. One should look in BESSETTEs book. But it is quite certain, that the American non-blueing regius is not identical with the regius ss. orig. in Europe.

I am almost convinced that the true European B.regius does not occur in California. And believe me, I have found several hundreds of specimens of this species since I am from Europe. This species shown here is no doubt closely related but a species of its own and much more brighter and more beautiful than the European mushroom is although B.regius is beautiful itself. And when there are very dry conditions B.regius must not stain blue, not even in the pores. This species here also reminds me of Boletus fuscoroseus but isn’t that either.
Maybe it’s undescribed?

…but your statement that it doesn’t blue is disturbing; at least the pores should stain blue.

if this is for science, and you saved it, more investigation is possible. If it tasted mild and you ate it, then that’s all she wrote. gorgeous material, regardless of its ID.

A quick scan of several Euro-images shows B. a. to have a brown cap, usually cylindrical stipe, and no obvious red colors. This is closer to B. regius in its red coloration, but the stipes seem too red for that, at least compared to a sampling of Euro-images.

Whether either of those names should actually be applied to California material remains to be seen.

was my first impression..

The color of the stipe and cap have me uncertain about the ID