This is a fruit from the tree I photographed and posted 3 days ago, http://365project.org/rhoing/365/2014-12-16
I still don't know what it is, but my hunch is that it's in the rose family (Rosaceae), which contains the pear (Pyrus), ash (Sorbus) and apple and crab apple genera (Malus). (This looks suspiciously like the fruit that grows on the tree in our front yard — http://365project.org/rhoing/365/2011-10-14 — which is supposed to be a "Cleveland pear."
This is my first photo with a background such as the botanists may use. It's not as dark a blue as my local expert uses, but I hope this will be adequate for now. (Dan — "Neon Blue" seemed to be the best that Hobby Lobby had at the time!)
Retired economics professor (“dismal scientist”). Married 40+ years to the love of my life; we have two grown daughters, both married, two granddaughters and a...