Annual or short-lived perennial herb to 1.5 m tall Stem: upright, branches ascending. Leaves: alternate, short-stalked, to 12 cm long, lower leaves lance- to egg-shaped with a tapering base and pointed tip, nearly pinnate and wavy-margined to merely toothed, progressively less toothed or non-toothed upwards, with tiny yellow glands. Inflorescence: a small, dense cluster of flowers (glomerule), which together form a long, slender, compound spike. Flowers: greenish, stalkless, small, with five sepals and no petals. Sepals glandular. Stamens five. Styles three to four. Fruit: one-seeded, enclosed in the persistent, incurved sepals, thin-walled. Seed horizontal or sometimes vertical, dark brown, shiny, 0.6 - 1 mm wide, thickly lenticular (lens-shaped), without margins.
Similar species: No information at this time.
Habitat and ecology: Introduced from tropical America. A weed often found in the waste places of towns and cities.
Occurence in the Chicago region: non-native
Etymology: Chenopodium comes from the Greek words chen, meaning goose, and podion, meaning "little foot," referring to the leaf shape of some species. Ambrosioides means "resembling Ambrosia."
Malodorous annual or short-lived perennial, erect, to 1(-2) m, with ascending branches; lvs beset with minute yellow glands, the lower blades lanceolate to ovate, to 12 cm, acute, deeply sinuate-pinnatifid to merely serrate, cuneate at base, the upper progressively less toothed or entire; fls sessile in small glomerules that are disposed in slender, somewhat elongate spikes, these in turn forming terminal panicles; cal 5-lobed, not obviously glandular; styles 3-4; seeds horizontal or some of them erect, thick-lenticular, not margined, 0.6-1 mm wide, dark brown, shining; 2n=16, 32, 64. Native of tropical Amer., established as a weed in gardens, roadsides, and waste places n. to Me. and Wis.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
A highly polymorphic species of wide tropical distribution, but adventive in the temperate zones. Found mostly in gravelly and sandy soil. Specimens with fewer bracts have commonly been referred to [variety anthelminticum] whose distribution is distinctly southern. It is probably much less common in the state than [variety euambrosioides].
Indiana Coefficient of Conservatism: C = null, non-native
Wetland Indicator Status: FAC
Diagnostic Traits: foliage with glandular-punctate, malodorous; lower leaves slightly toothed; inflorescences with many bracteoles longer than the adjacent flower-glomerules; fruits glandular-dotted, mostly horizontal, 0.5-1 mm wide.