Comments: The habitats of A. tuberosa seem to shift in going from east to west. From the tallgrass prairie ecoregion and eastwards, A. tuberosa occurs in prairies and dry woods or savannas, especially in sandy soils (Gleason and Cronquist 1963, Swink and Wilhelm 1994). In the Great Plains region, the habitat is described as roadsides and waste places (Great Plains Flora Association 1986). In the Rocky Mountain vicinity, the regional habitats described are near springs (in western Colorado) (Weber and Wittmann 1996a); in moist to somewhat moist, sandy (or sometimes gravelly) soils "in open ponderosa pine, oak, and pinyon-juniper communities," between elevations of 1300m and 2400m (in Utah and Arizona) (Cronquist et al. 1984); and in sage and mountain brush communities (in Utah) (Welsh et al. 1993).