Coefficient of Conservatism:
Coefficient of Wetness:
M. R. Penskar
Dry open places, especially with jack pine and oak, but also prairie-like ground, thin soil over limestone (Drummond Island), and sandy banks. This species ranges from the Great Lakes region to Iowa, and was originally described from the south end of Lake Michigan. Collections from southern Michigan are almost all quite old (Oakland Co. 1849–1896; Washtenaw Co. in 1867; Jackson Co. 1894–1896; St. Clair Co. in 1904; Berrien Co. in 1932; and Kalamazoo Co. 1931–1939), and the species is now very rare in this part of the state. The rosettes of spiny leaves, the plants to bloom another year, are often conspicuous in grassy areas of jack pine savannas.
A number of recent authors treat this taxon as subsp. hillii (Canby) R. J. Moore & Frankton or var. hillii (Canby) B. Boivin of the more eastern and southern C. pumilum (Nutt.) Spreng. All reports of C. pumilum from Michigan refer to this taxon, whatever rank one prefers for it.