This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Polygonum aviculare L. Sp. PI. 362. 1753. P. monspcliense Pers. Syn. 1: 439. 1805.
Annual, pale green or bluish green, stem low or ascending, simple or branched, 4'-2° long. Leaves broad, oblong to obovate-oblong, 13"-20" long, short-petioled, narrowed at the base, usually acute at the apex or sometimes obtuse; ocreae silvery, at length lacerate; clusters 1-5-flowered; flowers relatively large, pedicelled; sepals 5, green, except the white, pink or purplish borders, 1"-1 1/2" long; stamens 5-8; achene 3-angled, ovoid, 1 1/2"-2" long, acute, striate-rcticulatcd.
A weed in cultivated and waste grounds, common almost throughout North America, Asia and Europe. Bird-, beggar-, stone- or wire-weed. Door-, wire-, way- or crab-grass. Cow-, goose-, swine- or bird-grass. Bird's knot-grass. Bird's- or sparrow-tongue. Ninety-knot. June-Oct.
Annual, dull green, stem usually widely much-branched at the base, mostly 1°-2° long. Leaves narrow, elliptic to elliptic-bmceolate or linear, 3"-10" long, acute or somewhat acuminate at both ends, sessile or nearly so, those of the branchlets often conspicuously small and inclined to be obtuse; ocreae silvery-brown; flowers often 2 together, sessile or short-pedicelled; sepals green, except the pale pink to purplish-red margins, about 1/2" long; achene 3-angled, ovoid, about 1" long, acuminate, striate-reticulated.
A weed in yards, cultivated and waste grounds, nearly throughout North America, and common in nearly all parts of the north temperate zone. June-Nov.
Annual, stout, bright green or slightly glaucous, stem 1°-4° long, prostrate, diffusely branched from a woody base, striate. Leaves broad, oblong, oblong-lanceolate or oblanceolate or oval, 2 "-9" long, obtuse or subacute at the apex, thick, short-petioled; ocreae at length lacerate; flowers 2-6 in each cluster; sepals green, except the whitish margins, or carmine; stamens 8; achene broadly ovoid, 3-angled, l"-1 1/2" long, more or less contracted at the apex, dark-brown, the faces often granular.
On shores and in waste places, New Brunswick to Minnesota and British Columbia, south to Virginia, Illinois and New Mexico. Aug.-Sept. Mistaken in first edition for P. littorale Link, a European species with reddish-brown narrower and shining achenes, which has recently been reported from Mt. Desert, Maine.