Herbs, monoecious, typically erect and often branching, 3-15 dm; stems green or striped, angular. Leaves opposite or subopposite at least proximally; petiole 1-3 cm; blade strongly 3-veined from near base, lanceolate to linear-lanceolate or often triangular-ovate or lance-ovate, 30-125 × 25-60(-80) mm, thickened, basal or subbasal lobes spreading to mainly antrorse, obtuse, blade otherwise entire to sparingly dentate, typically scurfy. Flowers in terminal or terminal on lateral branches, in spiciform spikes, 2-9 cm, naked except at base. Fruiting bracteoles green, blackening in age, sessile, veined or veins obscure, broadly triangular to ovate, 3-10 mm, thick, usually longer than wide, base truncate to obtuse, margin united at base, apex acute lateral angles entire or with short, sharp teeth, faces smooth or with 2 tubercles, with an inflated inner spongy layer. Seeds ellipsoid, wider than long, dimorphic: brown, 1.5-3 mm wide, flattened at base, or black, 1-2 mm wide, shiny; radicle inferior. 2n = 36, 54.

Flowering summer-fall. Sea beaches, other saline habitats; 0-1500 m; Alta., B.C., Man., Nfld. and Labr. (Nfld.), N.S., Nunavut, Ont., Que., Sask., Yukon; Ariz., Calif., Colo., Idaho, Iowa, Kans., Maine, Mass., Minn., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Dak., Okla., Oreg., R.I., S.Dak., Utah, Wash., Wyo.

The distribution of the species is evidently bipartite, with an eastern coastal series extending northward mainly from New Jersey to Newfoundland and along the St. Lawrence seaway, and perhaps extending to James Bay of Hudson Bay. The western grouping lies mainly west of the 95th meridian of longitude, where it has been collected since early historical times to the present in saline marshes or other saline sites from the Yukon Territory and Northwest Territories, southward to southern California, northern Arizona, northern New Mexico, and Oklahoma.

Plant: Annual 5-15 dm; stem branched at base, generally erect; branches ascending, reddish to straw-colored at base, green-striate above

Leaves: blade 20-80(190) mm, lanceolate, green to reddish, sparsely fine-scaly, becoming glabrous, entire to toothed, base hastate; upper petioled

INFLORESCENCE: Staminate inflorescence: spike or spheric cluster; bracts 0; Pistillate inflorescence: bracts in fruit 3-7 mm, fused at base, ovate to widely triangular, surfaces with 2 spongy tubercles, base truncate to obtuse, margins few-toothed

Flowers: Staminate flower: calyx lobes 3-5; stamens 3-5; Pistillate flower: calyx ± 0; ovary ovoid to spheric, style branches 2

Fruit: Seeds of 2 forms (2-3 mm wide and brown, 1.5-2 mm wide and black)

Misc: Moist, saline or alkaline soils; < 200 m.