Carduus undulatus var. canescens: prairie thistle Site: Boulder Ridge, specimen 54 B; Collected: June 25th, 2012 Site: Boulder Ridge, specimen 54 F; Collected: June 25th, 2012 Site: Red Buttes, specimen 19 A; Collected: July 18th, 2012 Site: Red Buttes, specimen 19 C; Collected: July 18th, 2012 Site: Red Buttes, specimen 19 D; Collected: July 18th, 2012 January 26, 2016Wyoming Prairie Plants