Saxifraga micranthidifolia or Micranthes micranthidifolia
Last weekend, on Easter Sunday, we stopped in for a walk at Rock Castle Gorge near the Blue Ridge Parkway. Loads of wildflowers were in bloom, but I did find a new one (new for me at least) that caught my eye as we ascended the gorge trail. I knew it was a saxifrage of some kind, but it was bigger than others I’ve seen before. Each time I saw it, it was growing close to, if not actually in the stream bed.
Bright green, with succulent leaves, I wasn’t totally surprised to later learn that it is called “Mountain Lettuce” or “Brook Lettuce”. Both describe the plant and its habitat well.
The very handy book “Wildflowers of Tennessee and the Southern Appalachians” describes Brook Lettuce as perennial, with basal leaves up to 8 inches long, oblong, sharply toothed, tapering to a winged petiole. The tiny flowers about one-quarter inch wide, with 5 white petals, each with a pair of yellow marks at the base. The inflorescence is branched, forming a large open panicle. Mountain Lettuce habitat is wet cliffs and mountain brooks; bloom time is April-June.
As for the “lettuce” part of the common name, apparently this plant was eaten as a salad green in times gone by and is still gathered by foragers now. It can grow up to three feet in height, making for quite a salad! 🙂
Check out the photos!
VIRGINIA WILDFLOWERS 
Thank you for your apt descriptions. Isn’t it amazing that God could bring out of the dirt these dainty things so white?
I thought I was commenting on the white flowers! You call it lettuce; is it edible? I had a nice harvest of dandelion greens this week. Still eating them–sprinkle them amid salad greens. If they get too old I may just cook the remainder of the batch.