Mexican-tea, wormseed

Chenopodium ambrosioides Linnaeus, Sp. Pl. 1: 219. 1753; C. ambrosioides var. suffruticosum (Willdenow) Ascherson & Graebner; Teloxys ambrosioides (Linnaeus) W. A. Weber

Plants annual. Stems erect to ascending, much-branched, 3-10(-15) dm, ± glandular-pubescent. Leaves aromatic, distal leaves sessile; petiole to 18 mm; blade ovate to oblong-lanceolate or lanceolate, proximal ones mostly lanceolate, 2-8(-12) × 0.5-4(-5.5) cm, base cuneate, margins entire, dentate, or laciniate, apex obtuse to attenuate, copiously gland-dotted (rarely glabrous). Inflorescences lateral spikes, 3-7 cm; glomerules globose, 1.5-2.3 mm diam.; bracts leaflike, lanceolate, oblanceolate, spatulate, or linear, 0.3-2.5 cm, apex obtuse, acute, or attenuate. Flowers: perianth segments 4-5, connate for ca. ¹/2 their length, distinct portion ovate, rounded abaxially, 0.7-1 mm, apex obtuse, glandular-pubescent, covering seed at maturity; stamens 4-5; stigmas 3. Achenes ovoid; pericarp nonadherent, rugose to smooth. Seeds horizontal or vertical, reddish brown, ovoid, 0.6-1 × 0.4-0.5 mm; seed coat rugose to smooth.

Fruiting summer-fall. River bottoms, dry lake beds, flower beds, waste areas; 0-700 m; Ont., Que.; Ala., Ariz., Ark., Calif., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., Nebr., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis.; native to North America and South America, widely naturalized throughout the tropics and warm-temperate regions of the world.

Southern populations of Dysphania ambrosioides are native while those populations in the northern part of the flora area are introduced.