I'm not a mushroom specialist, but I think this is
russula cremoricolor in its young form. I'd never seen one of these before, but it's part of the story I'm working on so including it seemed important.
Schneider-Kreuznach APO-Symmar 100mm f/5.6 on an Arca-Swiss F-Universalis with Fuji GFX 100S.
The catch is my outfit isn't really made for this kind of photography. "Can get very close to the ground" is not on the list of strengths of an F-Universalis! Fortunately, the C1 Cube has this covered.
One of the nice bonus features of an Arca-Swiss F-Universalis is you can actually drive that rear standard well off the rail to get extra extension. As long as the gear in the rear standard (or "function carrier" in Arca-Swissish) is on the geared track, it's sturdy. My 150mm APO-Digitar works fine without a long bellows or rail because of this feature.