I'm a huge fan of rare/strange plants. I've always liked black flowers but this will be my first plant that actually has them. After going through a bunch of photos I'm convinced that the flowers should be very dark. Some are lighter and more of a deep purple, but most really are dark enough to be considered black. This is actually a plant I can leave outside all year.
Iris chrysographes prefers fertile, moist soil. Young plants should not be allowed to dry out. Seeds must be kept constantly moist. The easiest method is just to sow about 1/5cm deep in moist compost in the fall. Leave the outside all winter and they should sprout in the spring. They are rated for USDA zone 4.
Otherwise, you can stratify them in the fridge for two months in moist paper towel sealed in ziplock bags. The seeds need these cool temperatures and may actually germinate in the fridge. Plant them in pots as they germinate or after the two month period. There's actually a cool greenhouse at the local university that may be perfect for starting these!
My next post will be on a melon. This might seem normal, but it's not just any melon. It's the Cassabanana (Sicana odorifera).