I think it was because I was in a bit of a panic that might have little to send to the next Exchange that I picked some Iris seed heads (graminea and spuria ssp. maritima) and found they were not ripe. Too late to do anything else so I split the pods and put them on the kitchen windowsill in the hope that they might ripen. Have I wasted my time?
I also picked some seed heads from what I think is an Iris clarkei hybrid. Some of the seed is dark brown (which I take to be ripe?) and the other is a light brown. Is it possible that the light brown ones are unfertilised seeds ?