Macowanites luteolus is another member of the Russula family. It is an
intermediate form between a mushroom and a truffle; on the lower specimen
you can clearly see a vestigial stem. This vestigial stem extends all the way
through the middle to the top, forming a column of sterile tissue called a
columella. The upper specimen is cut perpendicular to the columella so you
see a cross section of it. The larger specimen here is about 1.5 inches across.