This midwestern species occurs mostly north of the Ohio Rv. and west of the lower Mississippi (K). It is closely related to australis and intermediate plants appear to exist in some cases, but there is no clear evidence of hybridization (Beal et al. 1982; F, FNA 22, W). Ranges overlap broadly in Ky., and there has been some confusion. S. brevirostra has generally longer fruiting pedicels (10-20 mm versus 3-12 mm) and larger heads (mostly 1.5-2.5 cm wide versus 1-1.5 mm), with somewhat depressed-globular shape (versus globular); achenes have obliquely ascending apices (versus ascending to strongly recurved); inflorescences are often branched (versus strictly simple); and petioles are less winged (ridged or "corrugated" versus sharply winged). Further research is needed to determine the degree of distinction.