Ambrosia artemisiifolia

Arsız zaylan

Annual, monoecious. Stem erect, branched, more than 40 cm, adpressed long-hairy. Leaves bipinnatisect, triangular to ovate-lanceolate in outline, up to 10 cm, lower ones opposite and petiolate, petioles up to 2 cm, upper ones alternate and sessile; leaves with short adpressed hairs, short glands and additional long soft hairs mainly on basal portions. Staminate capitula in spike-like, bractless, terminal racemes, elongating at anrhesis, up to 12 cm; capitula small, hemispherical, drooping, 10-15-flowered, pedicel 1 mm; involucre cup-shaped, 2-4 mm broad, crenately lobed, shortly hairy and glandular; receptacle scaly. scales narrowly linear-attentuate, with scattered glandular hairs; corolla yellow, regular, tubular, glandular, 1.5-2 mm, with 5 long-acuminate teeth; stamens 5, anthers oblong, 0.8 mm, with a broadly triangular apical appendage; gynoecium rudimentary with a short style. Pistillate capitula 1-2, in axils of uppermost leaves just beneath male inflorescence, each with a single floret; involucre 4 mm, apically beaked; corolla and pappus absent; style deeply 2-cleft, exserted from involucre: mature capitula not seen. Fl. 8. Damp acid grassland near coast. 10-20 m.

Native to N. America; naturalised in C. and S. Europe and in W.Caucasia, Recently introduced in Turkey.