Polygonum persicaria L.

• Authority

  Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

• Family

  Polygonaceae

• Scientific Name

  Polygonum persicaria L.

• Description

  Species Description - Erect or ascending annual to 8 dm, often much branched, glabrous or nearly so; lvs narrowly lanceolate, often with a dark blotch; ocreae membranous, strigillose, short-ciliate; spikes dense, straight, cylindric, 1–4 cm × 7–12 mm; ocreolae obliquely truncate, entire or with a few short cilia to 1 mm, pedicels mostly included; perianth pink or rose, 2–3.5 mm; achenes lenticular or occasionally trigonous, black, smooth and shining, broadly ovate, 1.8–3 mm, averaging four-fifths as wide; 2n=44. Native of Europe, now a common weed throughout our range, s. to Fla. and Tex., and w. to Alaska and Calif. (P. dubium; P. maculosum; P. puritanorum; Persicaria persicaria)

• Common Names

  lady's-thumb