Common name(s): Field thistle
Category: Genus Cirsium
Cirsium arvense
Common name(s): Canada thistle
Cirsium vulgare
Common name(s): Bull thistle
Wildflowers of the National Capital Region
Discovering wildflowers in Maryland, Washington D.C., and Northern Virginia
Common name(s): Field thistle
Common name(s): Canada thistle
Common name(s): Bull thistle