5. C. ambrosioïdes L.,

Sp. PI. 219 (1753); Bak. & C. B. CL in F.T.A. 6 (1): 79 (1909); Ulbr. in E. & P. Pf. ed. 2,16c: 491, Fig. 183 K-Q (1934); Aellen & Just in Amer. Midi. Nat. 30: 50-51 (1953); Hauman in F.C.B. 2: 2 (1951).

Type: Spain, Herb. Linnaeus (LINN, lecto.!)

Herb up to 120 cm. high, usually annual, rarely a short-lived perennial, polymorphic (principally in America),upright, much branched, green (? occasionally red-tinged), variably pubescent or hairy especially on stem, also with numerous yellowish sessile glands particularly on lower side of leaves, strongly aromatic. Leaves variable, lanceolate in outline to more rarely elliptic or obovate, mostly 1.5-10 cm. long and 0.4-4 3 cm. wide, entire to laciniate or pinnatifid; upper leaves and bracts smaller and narrower. Inflorescence an ample much-branched panicle with small sessile flower-clusters arranged spicately along the ultimate branches. Flowers greenish, 0-5-1-5 mm. in diameter. Sepals 3-5 (? flowers) 4-5 (? flowers), pubescent to glabrous, glandular, variably connate, smooth or very rarely keeled. Stamens 4-5. Pericarp easily removed. Seeds deep red-brown to blackish or shining, 0.5-1-25 (-1.5) mm. in diameter, bluntly keeled,testa under microscope almost smooth or shallowly and irregularly pitted, usually marked also with sinuose lines.