Polygonum persicaria lady’s thumb Polygonaceae POPE2*; Bx, br, pb, sf, wv (Yost et al. 1991); NY, ct, hb; Q, cu, ft, i, j, ri; K, cs, fs, p, m; R, fk, js, k, lp, pr, sm, t, w;


Polygonum persicaria.www.hawk-conservation.org

Polygonum persicaria.www.hawk-conservation.org (Accessed 4/2014).

Polygonum persicaria is an annual herb, 0.20-1 m tall, (plants on new fill piles or high nutrient soils often larger) taprooted, stem smooth, erect to reclining, often rooting at lower nodes in contact with soil, often branched, nodes often red, sheath appearing 2-parted, with a thicker, short, cup-shaped lower portion extending from the base of the leaf stalk, encircling the stem, above this is a longer, membranous sheath, sparsely covered with appressed bristles, the top fringed with bristles about 0.1 cm long or less. 

Leaves alternate, narrowly lance-shaped, 3-15 cm long, 0.5-3 cm wide, pointed at both ends, often dark-blotched above middle. 

Flowers pink (rarely white) about 0.3 cm long, bases of flowers from small membranous sheaths often with bristly upper margin, bristles 0.1 cm or less; inflorescence of 1-several crowded spike-like racemes 1.5-4 cm long, 0.7-1.1 cm wide, stalk smooth; blooming and fruiting June-Oct. 

Fruit dry (achene) lens-shaped, (occasionally 3-sided) 0.2-0.3 cm, black, shiny, eaten by many waterfowl, song birds and small mammals, plants eaten by muskrats (Martin et al. 1951). 

Wetland status: FACW. 

Frequency in NYC: Frequent. 

Origin: Europe. 

Habitat: Open or partly shaded wet soil, ditches, marshes, muddy fill, pH 4-8.5, extremely tolerant of a wide range of soils, moisture and light levels (Sultan et al. 1998; USDA, NRCS 2006). 

Note: Similar to P. lapathifolium but sheaths bristly.