Plant ID please
 

I'm in the piedmont area of South Carolina in a xeric pine tree
environment. I've been watching this plant during the summer, hoping
it would bloom and aiding me in ID'ing it but it hasn't and I haven't.

Above the ground it's a single erect stem (but often two or three
stems are within a few centimeters - from a common root?) with
alternating leaves. No petioles. At each leaf the stem bends slightly
(a joint?). The leaves appear to be trifoliate but the two smaller
side leaves are deeply cleft making it appear - sometimes - as 5
leaves. All leaves are toothed. It's not very common in my immediate
locale - have only seen three specimens in spite of many "walks in the
woods."

Be suspicious of my amateur's terminology.

See photos at http://www.flickr.com/photos/raphanus97/

Thanks.