Flowering Spurge, a native species, has been added to the USWildflowers database (08/30/2010.)  Scientific name is Euphorbia corollata.  Check out this really interesting plant. It is also is known by the common names Blooming Spurge and Emetic Root.  Photo below was taken in Haywood County, NC on July 12, 2010.

Flowering Spurge, Blooming Spurge, Emetic Root – Euphorbia corollata