Ambrosia artemisiifolia is native to North and Central America (Lorenzi and Jeffery, 1987; Kovalev, 1989). It is now widely distributed across the world; Africa (CJB, 2016), Asia (Flora of China Editorial Committee, 2011), Australia (Council of Heads of Australasian Herbaria, 2016) and Europe (Euro+Med, 2016).

Ambrosia artemisiifolia has become a dominant alien plant in countries such as Italy (Siniscalo and Barni, 1994), Lithuania (Gudzinskas, 1993) and Hungary. A. artemisiifolia is not as prominent in subtropical and tropical regions (Allard, 1943; King, 1966). The hot, dry summers in southern Europe and Mediterranean areas are not favourable for its growth (Allard, 1943; King, 1966). In addition to this A. artemisiifolia is relatively rare in northern Europe (Norway, Sweden, Scotland and Ireland) (Gerber et al., 2011).

Annual herb (therophyte), (10-)20-60(-150) cm tall. Stems erect. Leaves opposite (proximal) and alternate, with blades lanceolate or elliptic [(20-)25-55(-90) × 20-30(-50) mm], 1-2-pinnately lobed, sparsely pubescent abaxially, glandular-dotted on both faces, petioled [petiole 25-35(-60) mm long]. Flowers arranged in capitula, the male capitula (5-20 flowers per capitulum, the involucre being cup-shaped, glabrous to pubescent) forming a terminal spike-like inflorescence, the female capitula proximal to the male ones. Fruit globose to pyriform, 2-3 mm long, more or less pubescent.