[Atriplex hastata sensu Aellen, non L., more, Atriplex latifolia Wahlenb., Atriplex oppositifolia , Atriplex patula subsp. hastata sensu Hall & Clements 1923, non (L.) Hall & Clements, Atriplex patula var. hastata auct. non (L.) A. Gray, Atriplex patula var. triangularis (Willd.) Thorne & Welsh, Atriplex prostrata var. triangularis (Willd.) Rauschert, Atriplex triangularis Willd.]
The name for the species taken up here follows the nomenclatural interpretation of J. McNeill et al. (1983).
Herbs, monoecious, erect, decumbent or procumbent, branching, 1-10 dm; stems subangular to angular, green or striped. Leaves opposite or subopposite at least proximally; petiole (0-)1-3(-4) cm; blade triangular-hastate, lobes spreading, 20-100 mm and almost as wide, base truncate or subcordate, margin entire, serrate, dentate, or irregularly toothed, apex acute to obtuse. Flowers in spiciform naked spikes 2-9 cm, sometimes forming terminal panicles; glomerules tight, contiguous or irregularly spaced. Fruiting bracteoles green, becoming brown to black at maturity, triangular-hastate to triangular-ovate, veined or veins obscure, 3-5 mm, thin to thickened, spongy, base truncate to obtuse, margin united at base, lateral angles mostly entire, apex acute, faces smooth or with 2 tubercles. Seeds dimorphic: brown, flattened, disc-shaped, 1-2.5 mm wide, or black, 1-1.5 mm wide; radicle subbasal, obliquely antrorse to spreading. 2n = 18. Flowering in summer-fall. Sea beaches, salt marshes or other saline habitats; 0-2000 m; introduced; Alta., Man., N.B., N.S., Ont., P.E.I., Que., Sask.; Ariz., Calif., Colo., Conn., Del., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Oreg., Pa., R.I., Utah, Va., Wash.; Eurasia. Atriplex prostrata often grows with willow, tamarix, Scirpus (Schoenoplectus and Bulboschoenus segregates), Juncus, Distichlis, and Typha. Perhaps the phase along coastal eastern North America is indigenous, but this and the related Atriplex heterosperma evidently moved quickly from one palustrine habitat to another following subsequent introductions from the Old World. They were probably initially introduced as ballast waifs, and subsequently dispersed by waterfowl. The two species are now commonplace in lands within and adjacent to marshes in much of North America west of the initial sites of introduction.
Plants erect and to 1 m, or prostrate; lvs green, the principal ones 2-10 נ2-9 cm, hastate to triangular or rhomboidal, with sharp basal angles or lobes; infls lfless except at base; fruiting bracteoles foliaceous and somewhat (but usually not strongly) spongy-thickened toward the base, joined near the base, obscurely to ±evidently veined, 3-10 mm, triangular-hastate to triangular ovate, the lateral angles ±rounded, entire or toothed; seeds dimorphic; brown seeds 1.5-3 mm wide; black seeds harder, 1-2 mm wide; radicle inferior; diploid on x=9. On sea beaches and in salt marshes or saline soil inland; widespread in the N. Hemisphere, but in N. Amer. perhaps only intr. (A. patula var. h.; A. triangularis; A. franktonii)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Annual herb to 1 m tall Stem: upright, branched, green or striped, angled or nearly so. Leaves: mainly opposite, stalked, 2 - 10 cm long, nearly as wide, triangular to arrowhead-shaped with spreading lobes and a flat or nearly heart-shaped base and blunt to pointed tip, sometimes toothed, more or less mealy. Inflorescence: a 2 - 9 cm long spike of flowers or a branched cluster of flowers (panicle). Flowers: either male or female, borne on the same plant (monoecious), greenish, tiny. Male flowers with five sepals and stamens, no petals. Female flowers without petals and sepals, enclosed within a pair of small, leaf-like bracts (bracteoles). Stigmas two. Fruit: enclosed within a pair of small bracts (bracteoles). Bracteoles united at base, green becoming brown to black, 3 - 5 mm long, triangular arrowhead-shaped to triangular egg-shaped with a flat to rounded base and pointed tip, mostly non-toothed, smooth or with two small projections, spongy. Seeds brown, 1 - 2.5 mm wide, disc-shaped, and flattened, or black and 1 - 1.5 mm wide.
Similar species: The similar Atriplex patula idiffers by the shapes of its leaves, which are most often non-toothed or very sparsely toothed along the margins.
Flowering: August to September
Habitat and ecology: Introduced from Eurasia. Found in a wide variety of disturbed habitats, including lawns, gardens, parkways, and waste ground. May also be found along highways because it tolerates a high degree of salinity.
Occurence in the Chicago region: non-native
Etymology: Atriplex is the ancient Latin name for this plant. Prostrata means prostrate.