Scarletina bolete/Gewone heksenboleet

The big one and the two right small photo's are Boletus erythropus var. erythropus. They have a brown cap. The left two specimen of the small photo's have yellow caps, giving it the name Boletus erythropus var. discolor, which is a rarity in the Netherlands!
They are also known as Boletus luridiformis, but with the new taxonomic rules, B. erythropus is the right name to use.

http://www.rogersmushrooms.com/gallery/DisplayBlock~bid~5615~source~gal…
http://boletales.com/genera/boletus/b-luridiformis/
http://www.first-nature.com/fungi/boletus-luridiformis.php