Once I knew the name, of course, an online search found tons of hits. I liked this page and this post.
It really is a lovely little flower. Sadly it's already gone. I don't know if it was eaten by the bunnies or if it just naturally died out.
In other exciting gardening news, the first irises flower stems are shooting up! I think our first irises bloomed in early May last year, so we still have a few weeks before they bloom, but I'm excited to see if the ones we transplanted do well this year. We still have seven or eight bunches to divide.