American Lopseed, a native species, has been added to the USWildflowers database (11/18/2013.) Scientific name is Phryma leptostachya.  It is also known simply as Lopseed; the “American” is added to differentiate from an Asian plant which may or may not be the same species, depending on the authority to whom you subscribe.  Photo below was taken at Camp Vesper Point in Hamilton County, TN on Aug 16, 2013.  Go to the American Lopseed detail page for more photos and information.

American Lopseed – Phryma leptostachya