Cirsium scariosum Nutt.
Thick, leafy, unbranched succulent stems vary from 2 to 3 inches to 4 feet. White to purple flowers are clustered together. Leaves are toothed or deeply dissected;. Entire plant is covered by spines. It flowers from June to the first part of August. .It is found in moist to wet soil, usually in open meadows from valleys to about 8,000 feet. Reported by Nuttall on the plains of the Rocky Mountains, thought by Moore and Franklin to be just north of Wyeth's Fort Hall in the present Bingham County, Idaho.
Roots may be eaten raw, roasted, fried, pit baked.
Roots of this thistle and others used as a poultice over wounds, swellings. Root decoction used for many purposes to include treating back pain.