Kot

Tylopilus are poisonous?

But taste is not bitter and spore side became dark after finger pressing

There is the point of confusion: They look like boletus but the top film possible to remove like from Suillus granulatus; the spore side became dark like on Leccinum scabrum if press under cup; taste is no bitter, light sweet. Therefore, it was NO ONE worm in old large one (not usual for good boletus).

What is the name of these mushrooms, I found under oak trees