Mountain thistle (Cirsium scopulorum) belongs to the Asteraceae (the Aster family). It is a perennial herb that is native to the southwestern United States, Utah, Wyoming, Colorado and New Mexico. This herb grows in subalpine to alpine, openings and screes, and up to a height of 50-150 cm. The stem is erect, and the leaves are narrow, often hairless and shiny. The whole plant is very prickly. The white, yellow, pink to purple flower-heads bloom from July to September.