Cirsium undulatum (Nutt.) Spreng.

Cirsium undulatum (Nutt.) Spreng.. Cirsium undulatum is a species of thistle known by the common names wavyleaf thistle and gray thistle. It is native to much of central and western North America from British Columbia east to Manitoba and south as far as the State of Durango in Mexico. It has also been found outside of its native range as an introduced species.