This variable weedy species is widespread across eastern North America (Semple & Chmielewski 1985, FNA 20); 2n = 32 (mostly southeastern including central and e. Ky.), 40 (occasional in transitional range) and 48 (mostly midwesterm includiing w. Ky.). It is especially common in old fields with little mammalian herbivory (e.g. Bowers 1993). Several segregates have been treated as varieties or species, but distinction is difficult in some cases. Typical pilosus usually has dense hairs on stems and leaves, those on stems relatively long (up to 0.5-1 mm) and curling. Ray color is usually white but Semple & Chmielewski (1985) found that " bluish or pink-rayed plants.. were encountered throughout the range and always had pubescent stems." See also notes under parviceps, juniperinum and priceae, which can be confused. Broad-leaved colls. (from CLAR, KENT, POWE, ROWA, SCOT and elsewhere) have been referred to var. platyphyllum Torr. & Gray, when treated in Aster, but that taxon has not been recognized in recent treatments (e.g. FNA 20). S. pilosum and its allies (as listed above) all have inrolled phyllary tips, and leafy tufts are usually present at plant bases. Although this group (subsection Porteriani) is distinct from other "little white asters" (subsection Dumosi), hybrids can be expected, especially between pilosus and lateriflorum or lanceolatum (Semple et al. 2002, and pers. comm.).