Sanguinaria canadensis; Papaveraceae (poppy family)

In another day or two, the basal leaf should be fully open.  The leaf can be quite large and the look is unique.  There’s no mistaking bloodroot once you’ve seen it, even though the flowers can vary in appearance:

One plant can send up several stalks, but each stalk bears only a single blossom and leaf.  Apparently bloodroot can form large colonies, though I’ve never found one.  Yesterday I saw seven individual flowers in a 50 square foot area: not quite a colony, but a large concentration.