Canada Thistle (Cirsium arvense)
Above: Canada Thistle photographed in Carroll Co., Maryland (6/16/2007).
Comments: Native to Eurasia, introduced to the U.S. in the 1600s, probably with crop seed shipments.
Above: Canada Thistle photographed in Carroll Co., Maryland (6/16/2007).
Comments: Native to Eurasia, introduced to the U.S. in the 1600s, probably with crop seed shipments.