Cirsium scariosum var. coloradense
Variety coloradense is common in the mountains of southern and central Colorado with outlying populations in northern New Mexico, northeastern Arizona, central Utah, and southeastern Wyoming. In Colorado it is largely allopatric with the usually acaulescent var. americanum. Some plants from the White Mountains and San Francisco Peaks of Arizona and from Gunnison County, Colorado, approach var. thorneae in having deeply divided, extremely spiny distal leaves that overtop the heads. Putative hybrids between var. coloradense and Cirsium grahamii have been documented in Apache County, Arizona, and between var. coloradense and C. undulatum in Las Animas County, Colorado.