Comments: Two subspecies of A. racemosa are often recognized (e.g, by Kartesz, 1999): subsp. bicrenata, found in Texas, New Mexico, Arizona, Colorado, and Utah; and subsp. racemosa, found in the remainder of the species' extensive range in eastern North America (Kartesz, 1999; USDA-NRCS 1999, Weber and Wittmann 1996a, Weber and Wittmann 1996b). The populations in northern New Mexico are likely A. racemosa subsp. bicrenata.