I've been waiting for ages to see this plant in the flesh. Terra Nova teased me with a slide and a press release a few years ago, but when I asked them please to send a plug, they were all out. Grrrr. So yesterday, I'm taking a quick trip around the back gardens at Sara's in Brockport (quick because it's raining and I'm cold), when this little guy leaps out at me.
Mukdenia rossii 'Crimson Fans' is a petite groundcover for shade (yes, it will grow under trees—I've seen the green version doing well there at Cornell Plantations). I won't describe the foliage as you can see it for yourself here, and I haven't seen flowers or pictures of flowers, but being that it's a close relative, I image they're similar to that of garden saxifrage.
I didn't see Kathy to ask her whether she had any in stock, but if it's in her display garden, it can only be a matter of time.