This occurs mostly in the Ozark region and in the western Interior Low Plateaus, largely restricted to mesic or subxeric woods and flowering relatively early (late May-early Jun) . F and Cr insisted that M. russeliana Nutt. is the correct name for this species, but that is generally not accepted (McClintoick & Epling 1942, Scora 1967, W). The name russeliana is generally restricted to the distinct Ozarkian species also known as M. virgata Raf. That species is highly variable in leaf width andf head size, but segregates have not been well defined. Some colls. appear transitional to bradburiana, but there is no definitive evidence of hybrids in the wild (A. Prather and A. Floden, pers. comm.). M. bradburiana is distinguished from russeliana sensu stricto as follows (from above refs. and pers. obs.): corolla with unexpanded tube 3-6 mm long (versus 8-12 mm); the lower lip 15-20 mm long (versus 12-16 mm), slightly incurved but with an abruptly upturned (outcurved) bifid apical extension (versus strongly inrolled, without distinct bifid extension); the upper lip apex somewhat comose, with denser longer hairs (versus no so); leaves 2-5 cm wide (versus 1-3 cm), not distinctly lustrous (versus distinctly so); calyx lobes ca. 2-4 mm long (versus 1.5-2 mm), with minute glandular-stipitate hairs (versus stout stipitate hairs).