Cow Soapwort, an introduced species, has been added to the USWildflowers database (03/16/2013.) Scientific name is Vaccaria hispanica.  It  is also known by the common names Cowcockle and Cowherb.  Photo below was taken along the Kleinschmidt Grade, Adams County, ID, on June 19, 2011.   Go to the Water Cow Soapwort detail page for more information.

Cowcockle, Cow Soapwort, Cowherb – Vaccaria hispanica