This is probably native to warmer regions of the Americas, but now widespread across North America. The ambrosioides complex varies much in chromosome number (2n = 16 to 64) and several varieties have been proposed; see also notes under anthelminticum. Distinction of the genus Dysphania from Chenopodium has much phylogenetic support, but the only consistent morphological difference is as follows (FNA 4, W; and citations): plants covered with stalked glandular trichomes, sometimes plus subsessile glands or uniseriate multicellular trichomes, sometimes glabrescent but rarely farinose (versus farinaceously pubescent with small white inflated hairs or glabrous), usually aromatic and malodorous to humans (versus not notably aromatic, often edible although sometimes bitter). There is also a tendency for fewer perianth segments, 1-5 (versus usually 5); and fewer stamens, 1-5 (versus usually 5). The chemistry of ambrosioides includes monoterpenes with diverse physiological effects that are potentially adverse for particular bacteria, flatworms, mosquitos and other insects (e.g. Bezerra et al. 2019, Almadiy 2020). There is long history of medicinal uses by humans, and productive research is continuing (e.g. Hurrell 2018).