Chenopodium ambrosioides L.

DeFilipps, R. A. & Maina, S. L., 2003, Chenopodiaceae, Flora of the Guianas, Kew: Royal Botanical Garden, pp. 61-64 : 62-64

1. Chenopodium ambrosioides L. , Sp. Pl. 219. 1753

Type: Herb Linneus No. 313.13 (LINN, not seen).

Annual or perennial, taprooted herb. Stem 0.3-l.0(-1.5) m tall, strongly scented of mustard, ribbed, often somewhat woody, much-branched. Petiole 1-2 cm long; blade lanceolate, oblanceolate, oblong-elliptic, rhombic-elliptic or ovate, 0.6-12.5 x 1-5.5 cm, entire to shallowly dentate OI' sinuately pinnatifid, apex acute to obtuse, sometimes apiculate, base cuneate, sessile glandular resin dots, especially on lower surface, glabrous or sparsely puberulent above, or puberulent beneath especially on veins, yellowish-green. Inflorescence a single cyme Of spikes of cymes; flowers in glomerules of 4-6, along major axes, in groups of 1-3 on apical, minor axes; glomerules 1-bracteate, bract linear to (sub)foliaceous, to ca. 2.5 cm long; flowers sessile or subsessile. Tepals (3-)5, greenish, narrowly ovate, 0.7-1.3 mm long, glabrous OI' puberulent and usually gland-dotted, fused ca. half-way, cucullate and folded over fruit; stamens (3-)5; filaments about as long EIS tepals, anthers orbicular, 0.5 mm long; stigmas sessile or subsessile, spreading. Pericarp not adherent to seed, thin and decaying; seeds lenticularcochleate to ovoid, 0.6-0.8 mm in diam., horizontally or vertically oriented, smooth, lustrous, reddish-brown.

Distribution: Possibly native to Mexico and Central America, now a cosmopolitan weed in Warm regions; 21 collections examined, all from the Guianas (GU: 6; SU: 1; FG: 14).

Selected specimens: Guyana: South Rupununi Savanna, Aishalton airstrip, Henkel 3467 (US); Rupununi Savanna, Cook 250 (NY, U); Ireng R. near Orinduik Falls, Essequibo County, Irwin et al. 474 (US). Suriname: Cultis, Focke 1395 (U). French Guiana: Cayenne, Jardin pnma, Kodjoed 91 (CAY); Commune de Remire, Ile de Cayenne, Wittingthon 59 (CAY).

Uses: Generally found as a Weed, sometimes cultivated as a medicinal plant for the leaves, which are used as an anthelmintic (vermifuge) in the Guianas (Cook 250; Ostendorf (1962); and Moretti 913). The French Guianans use an infusion of six leaves mixed with salt in a cup, which is reportedly very beneficial for the liver, and as a children's vermifuge (Oldeman B.3909). According to Henkel 3467, the plant is used as a malaria treatment by Wapishiana Amerindians of Guyana.

Vernacular names: Guyana: matouosh; mastruz (Portuguese Guyanese); metroshi (Macushi Amerindian). Suriname: tingi-menti; woron-menti (Creole). French Guiana: Woron-wiwiri (Boni); aapoa (Wayapi); zerba vers, poudre aux vers (Creole); semen contra.