The accepted name is I. ensata. I. kaempferi is a synonym. I. laevigata is a different iris.
Irises sold as Japanese irises or I. ensata should be pure ensata. Hard to believe, I know, from what they look like today. The Japanese first bred from variants found in the wild. What you see today is the result of many years of selective breeding resulting in flowers that look quite different from the species.
Here are a few of my Japanese iris seedlings (from protected crosses):
Coho x Reisyun
Indigo Delight x Summer Splash
Freckled Geisha sdlg x Blue Embers
Japanese irises are as fun as lilies to play with. Seedlings are a lot easier to handle too.
Here is an ATP article I wrote a while back on color patterns of Japanese irises.
http://garden.org/ideas/view/p...