"What ARE those green things? Monkey brains?" asked over my shoulder as I published the post below.
In case you've never seen them, those strangely textured balls are Osage oranges, the fruit of the Osage (or Bow-wood) tree. You may have also heard them called Hedge Apples, for pioneers often planted starts of them for living fences. I always gather a bag or two when I see them by the roadside. I love their acid green color and sweet scent. A big bowlfull makes a free seasonal centerpiece!
A great book with a chapter about the Osage tree is Susan Munger's Common To This Country: Botanical Discoveries of Lewis and Clark. Its fantastic illustrations really enriched my understanding of their journey.