All at once I remembered a long ago episode (Amok Time) of Star Trek in which the non-emotional Mr. Spock is suddenly ... umm ... in a state of rut and must return to his home planet to find a Vulcan mate.
Anyway, as I recall it (and this was a very long time ago,) there was a big ceremony when Spock came home and everyone carried staffs with jingly things on them. Which is what the mystery thing reminded me of.
You all probably knew what it was at once or, at least before I got to the third paragraph.
Back last spring, it had pretty purple flowers . . .
And by summer it was covered with round seed pods . . .
When the seed pods dry, you can peel off the outer coat to find the seeds and the shiny interior membrane.
Lunaria, Money Plant, and Honesty are some of its names. But, at least in its final stages, I'm going to think of it as a Vulcan Jingly Thing Plant.