The big news in the woods today is that virtually all of the acorns have popped out of their caps today. The only ones that I saw still attached to their caps were a few immature ones such as 8214. I would love to have seen the detaching. I did see a few still sitting near their caps and one with the umbilicus detached but the cap still loose on the acorn. What could the signal have been? My son M with whom I was discussing this matter thought shrinking of the acorn due to dryer air. Makes sense to me.