1.
Dysphania ambrosioides
(Linnaeus) Mosyakin & Clemants, Ukrayins'k. Bot. Zhurn., n. s. 59: 382. 2002.
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.
