The USDA Plants Database name for this species is peculiar since most other references call it Purple Cress or Northern Bittercress. I’m not sure how it got “Limestone” in its name. The only places I’ve seen it is in rich woods in the early spring. It’s really quite lovely, especially since it blooms so early when you’re sick and tired of winter and anxious to see some wildflowers.
I think Purple Cress is a bit of a stretch as well, since the flowers are generally only pale purple, perhaps more of a lavender. Maybe it should be called Early Spring Lavender Cress.