Foothills, montane. Woodlands, openings. Spring, summer.
Navajo Reservation near Teec Nos Pos, Arizona, June 24, 2006.

This compact, short thistle is a fortress of spines with a cylindrical flower head emerging from a pineapple-like bud. The pineapple appearance is due to the phyllaries, the whorl of triangular, overlapping bracts subtending the flower head. It grows in low Pinyon-Juniper forests, often in rock areas.

The genus was named by Phillip Miller (1691-1771).  The species was at first named Cnicus drummondii by Alice Eastwood in 1893 from a specimen she collected near present day Mesa Verde National Park.  It was renamed Cnicus calcareus by Marcus Jones in 1895 and then Cirsium calcareum in 1915 by Elmer Wooton (1865-1945) and Paul Standley (1884-1963).

"Calcareum", Latin for "spur" or "limestone", could refer to a spur on the Thistle or to calcareous soil conditions.

Foothills, montane. Woodlands, openings. Spring.
Head of Hovenweep Canyon, June 8, 2001.

Cirsium tracyi is a native and very common Thistle, especially in low, semi-desert, dry, open areas.  It has numerous puffy white (sometimes pink-to-lavender purple) flowers which at first appear to be dried seed heads.

This plant was first collected for science by Charles Baker and Samuel Tracy near Mancos, Colorado in 1898 and was at first named Cardus tracyi by Per Axel Rydberg in 1905 and then renamed Cirsium tracyi by Franz Petrak (1886-1973) in 1917.  Several plant authorities, including the USDA Plant Database and Synthesis of the North American Flora now consider Cirsium Tracyi to be a variety of Cirsium undulatum.  It was so designated by Stanley Welsh (of Utah Flora fame) in 1983.  Tracy was a late nineteenth/early twentieth century plant collector. (More biographical information.)

Foothills. Woodlands, openings. Spring.
Canyons of the Ancients National Monument, June 12, 2005.

Foothills. Woodlands, openings. Spring.
Head of Hovenweep Canyon, June 8, 2001.