For an introductory discussion of these things, see my weblog entry of July 21.
Carpels of Peonia officinalis subsp villosa.
Open carpels of Paeonia mollis. I was rather suprised to see that the seeds of this species are apparently ripe, since the carpels have opened. However the seed doesn't quite have the look of fully developed seed so it is possible that they are all aborted seed, causing the carpels to open earlier than would usually be the case.