Pringle's Aster, aster de Pringle
Symphyotrichum pilosum var. pringlei (A. Gray) G.L. Nesom is native to the northern portion of the range of S. pilosum. It has hairless stems, leaves and heads (Brouillet et al. 2006 FNA). Stem height is highly variable with the shortest plants growing on limestone alvars and taller plants growing in sandy soils. The latter were described from southeastern Virginia as a Aster pilosum var. demotus but the taxon should not be recognized. Tall plants collected in the field can be very short when grown in limited soil. Throughout the range the variety is hexaploid (2n=48; Semple and Chmielewski 1985). Hexaploid plants of S. parviceps from eastern Missouri can be confused with glabrate forms of S. pilosum var. pringlei, but the taxon does not grow that far to the southwest.