Symphyotrichum racemosum

Small White or Smooth White Oldfield Aster

Symphyotrichum racemosum (Ell.) Nesom is native to moist to wet, often alluvial soils, often brackish, marshes, savannas, bogs, wet meadows, prairie swales, swamps, borders of swamps, and open bottomwoods in the eastern US from southern Maine to Illinois south to northern Florida and east Texas (Brouillet et al. 2006; FNA). Reports for the species from New Brunswick and Ontario are likely for plants of Sy. dumosum or Sy. lateriflorum, which are close relatives of S. racemosum.  The disc floret corolla lobes of S. racemosum are 0.5-1 mm long and shorter than those of S. lateriflorum. The species was treated as Aster vimineus Lam. for many years but that name was misapplied. Aster dumosus L. var.  subracemosus Torr. & A. Gray is a synonym and includes plants with heads on longer peduncles and branches than the typical short peduncle form. The species includes diploids 2n=16 and tetraploids 2n=32.  Semple et al. (2024) summarized all previously published chromosome counts and reported new counts for the species and presented a cytogeography map of all counts for S. racemosum.