This one was photographed about a week earlier.  It is younger then those shown on first page and there is the purple highlight that does not show in older specimens.  This one is about 4" in the longest dimension.
I would assume that this is a different species since it has a stem and a different color.

This is the side view of the one shown above.  It was growing out of leaf litter and a short stem is hidden by the leafs

Close-up of the 1" stem after removing leaves.

Here is still a younger specimen.

What do you think?  Is it a Common Brown Cup or not?