Black Cohosh

Cimicifuga racemosa
Cimicifuga americana
Buttercup Family

Also may be known as Black Snakeroot or Bugbane. These are large (up to 8 ft. or so), summer blooming plants grow in rich woods. At the time I photographed this one I didn't know there were two similar species, Mountain Bugbane C. americana   is less common, grows at higher elevations and is different in the flowers with  three or more  pistils in each flower, whereas C. racemosa has just a single pistil.