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..
Annual or perennial glabrous herbs, sometimes slightly woody, with erect branched usually conspicuously jointed stems, alternate narrow leaves articulated to the ocreae, and small white or greenish flowers in slender panicled racemes. Calyx unequally 5-parted, persistent, its segments petalloid, loosely investing the achene or its base in fruit, the three inner calyx-segments often winged. Stamens 8, included; filaments filiform, or much dilated or auricled at the base. Style 3-parted, short or almost wanting; stigmas capitate; ovary i-celled; ovule solitary. Achene 3-angled, smooth. Embryo slender, nearly straight, in one of the angles of the seed. [Diminutive of Polygonum.]
Annual; inner sepals not winged in fruit; pedicels reflexed.
P. ar tic ul at a.
Perennial; inner sepals winged in fruit; pedicels divergent.
Polygonum articulatum L. Sp. PI. 363. 1753. Polygonella articulata Meisn. Gen. 2: 228. 1836-43.
Annual, glaucous, stem slender, wiry, erect or sometimes diffusely spreading, simple or branched, striate or slightly angled, 4-10' long. Leaves linear or linear-subulate (apparently filiform from the revolute margins), sessile, 4"-2o" long, jointed to the summits of the ocreae, cylindric, slightly expanded at the summit; racemes numerous, erect, many-flowered, 1'-1 1/2' long; ocreolae crowded or imbricated; pedicels reflexed; calyx-segments white with a dark midrib, loosely investing the achene, not winged in fruit; achene narrowly ovoid-pyramidal, pointed, 1" long, brown, smooth, shining.
In sands of the seashore and sandy soil along the coast, Maine to Florida, and on the shores of the Great Lakes. Sand-grass. July-Oct.
Gonopyrum americanum F. & M. Mem. Acad. St. Petersb.
Hist. 5: 230. 1845. P. americana Small, Mem. Torr. Club 5: 141. 1894.
Perennial by a long slender root, slightly glaucous, stem erect or ascending, wiry, somewhat flexuous, 1 1/2°-4° high, simple or slightly branched, covered with a ridged more or less scaly bark. Leaves linear or linear-spatulate, 1/4'-1' long, often fascicled on short branches, sessile, rather fleshy, obtuse and revolute at the apex; ocreae scarious-margined, split on one side; racemes 1'-3' long, dense, divergent; calyx white or pink, its three inner segments developing orbicular cordate wings, the two outer reflexed in fruit; pedicels divergent, jointed below the middle; achene elliptic-oblong, 1 1/4" long, chestnut-brown, pointed at both ends, smooth, shining.
In dry soil, Missouri to Texas, east to Georgia and Alabama. Aug.-Oct.