Saponaria officinalis L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Colonial by rhizomes, erect, 4–8 dm, mostly glabrous; lvs 7–10 × 2–4 cm, elliptic to elliptic-ovate or lance-elliptic, acute; infl congested and subcapitate to open and oblong- pyramidal, to 15 cm, the primary bracts leafy, the ultimate ones scarious; fls fragrant, often double; cal 1.5–2.5 cm, the lobes triangular-attenuate, the tube often becoming deeply bilobed; pet white or pinkish, the auricles none, the appendages conspicuous, the blade 8–15 mm, oblong to oblong-obovate; stamens exsert; 2n=28. Native of the Old World; formerly cult. and now established as a weed of roadsides and waste places or along railways throughout most of temperate N. Amer. Summer.