Plants 40-200 cm; basal offshoots, stolons present or absent. Stems erect to ascending. Leaf blades linear to narrowly oblanceolate or linear-obovate; cauline 76-140 × 18-26 mm, bases not decurrent. Heads in paniculiform arrays, branches spreading to ascending; bracts 7-35 × 1-5 mm. Peduncles 8-58 mm; bracts 1-3, linear to linear-subulate, 1-2 mm. Involucres 2-5 × 3-7 mm. Phyllaries in 2-3 series, linear-subulate, subequal, (0-)1-3(-5) merging down peduncles; outer 1.2-1.6 × 0.2-0.4 mm; inner 1.9-2.2 × 0.3-0.5 mm. Ray florets 25-36; corollas white to lilac, laminae 3-7.5 mm, tubes 0.5-0.7 mm. Disc florets 100-170; corollas 1.7-5 mm. Cypselae obovoid, 1.4-1.6 × 0.8-0.9 mm, wings 0 or 0.01-0.1 mm wide, faces mostly glabrous; pappus awns 0-0.4 mm. 2n = 18.
Mostly 8-20 dm; lvs lanceolate to linear-oblanceolate, or the lower broader, tapering to both ends, the larger ones mostly 8-15 נ1-2.5 cm, some of those present at full anthesis generally at least 1 cm wide; infl diffusely branched, somewhat leafy, the lvs mostly narrower and over 1 cm; invol bracts narrow, acute, subequal or slightly imbricate, rays white (lilac), mostly 5-8 mm; disk mostly 3-6(-8) mm wide; achenes scarcely or only very narrowly wing-margined; pappus-awns minute, less than 0.5 mm; 2n=18. Moist lowlands; coastal plain and piedmont of s. Va. to S.C. (B. ravenelii, with unusually large heads)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.