Polygonum aviculare subsp. aviculare

Plants green, heterophyllous (often lacking larger proximal stem leaves at maturity). Stems 1-3, ascending or erect, sometimes decumbent, basal branches divar-icate, (10-)25-75(-100) cm. Leaves: ocrea (5.5-)6-10(-14) mm, proximal part cylindric, distal part silvery, hyaline, soon lacerate and disintegrating into fibers; petiole 1-6(-8) mm; blade green, lateral veins visible but not raised abaxially, elliptic to oblanceolate, 18-50(-60) × (6-)10-20 mm, 2-4.5 times as long as wide, apex acute or obtuse; stem leaves 1.4-4 times as long as branch leaves. Cymes aggregated at tips of stems and branches, 3-8-flowered. Pedicels mostly exserted from ocreae, 2-5 mm. Flowers: perianth (2.3-)2.8-4.7(-5) mm, 1.8-2.8 times as long as wide; tube (15-)20-37% of perianth length; tepals overlapping, green with pink, red, or white margins, oblong, flat (cucullate in fruit), outer tepals not pouched at base; veins branched, thickened; stamens 7-8. Achenes enclosed in or barely exserted from perianth, brown to dark brown, ovate, 3-gonous, (2.1-)2.7-3.7 mm, faces subequal, concave, apex straight, striate-tubercled; late-season achenes uncommon, 3.5-5 mm. 2n = 40, 60.

Flowering May-Oct. Fields, uncultivated areas, waste places, roadsides; 0-3500 m; introduced; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., La., Maine, Md., Mass., Mich., Minn., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., Wyo.; Eurasia.

From Flora of Indiana (1940) by Charles C. Deam

An annoying weed in gardens, truck gardens, lawns, pastures, and cultivated fields. It is found, also, along logging roads in woodland, in fallow fields, and along roadsides.