Dysphania ambrosioides (L.) Mosyakin & Clemants

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

Dysphania ambrosioides s.l. is a taxonomically complicated aggregate of several closely related segregate “microspecies” and/or infraspecific taxa. Judging from the herbarium material available, there are several entities naturalized in China. However, their taxonomy and distribution in the Flora area are not well understood, and because of that they are not discussed here.

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.

Herbs annual or perennial, 50-80 cm tall, with strong odor. Stem erect, much branched, striate, obtusely ribbed; branches usually slender, pubescent and articulated villous, sometimes subglabrous. Petiole short; leaf blade oblong-lanceolate to lanceolate, abaxially with scattered glands, slightly hairy around veins, adaxially glabrous, base attenuate, margin sparsely and irregularly coarsely serrate, apex acute or acuminate; lower leaves ca. 15 × 5 cm, upper ones gradually reduced and margin subentire. Flowers borne in upper leaf axils, usually 3-5 per glomerule, bisexual and female. Perianth segments (3 or)5, usually nearly closed in fruit. Stamens 5; anthers ca. 0.5 mm. Style obscure; stigmas 3(or 4), filiform, exserted from perianth. Utricle enclosed by perianth, depressed globose. Seed horizontal or oblique, black or dark red, sublustrous, ca. 0.7 mm in diam., glabrous, rim margin obtuse. Fl. and fr. over a lengthy period.

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.

Fruiting summer-fall.

River bottoms, dry lake beds, flower beds, waste areas; 0-700m.

Naturalized; often cultivated for medicine in N China. Fujian, Guangdong, Guangxi, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang [native to tropical America; now widely naturalized in tropical, subtropical, and warm-temperate regions of the world].

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

Chenopodium ambrosioides Linnaeus, Sp. Pl. 1: 219. 1753; Ambrina ambrosioides (Linnaeus) Spach, nom. illeg.; Atriplex ambrosioides (Linnaeus) Crantz; Blitum ambrosioides (Linnaeus) G. Beck.