Sanguisorba minor Scop.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Perennial from a caudex-like rhizome; stems 2–7 dm; lower lvs numerous and well developed, with usually 7–17 lfls, the upper lvs progressively reduced; lfls ovate to rotund, 5–20 mm, with 3–7 sharp teeth on each side; heads several on elongate peduncles, short-ovoid to globose, 8–20 mm; fls subtended by ciliate bracts, the lower ones perfect or staminate, the upper pistillate; sep green or brown, 2.5–5 mm, the inner pair broader than the outer; stamens numerous, the long filaments drooping; pistils 2; mature hypanthium 5 mm, very rough between the wings; achenes 2, semi-ovoid; 2n=28, 56. Native of Eurasia, established as a weed along roadsides and in fields and waste places here and there in our range. May, June. (Poterium sanguisorba)