Ambrina Spach sect. Adenois Moquin-Tandon, Chenop. Monogr. Enum., 39. 1840

Plants annual or perennial. Leaf blades with margins entire to pinnatifid. Inflorescences linear-spicate or spicate-paniculate, ± foliose with flowers clustered in dense glomerules. Flowers: perianth segments (3-)4-5, connate basally; stamens 4-5; styles (2-)3(-5). Seeds mostly horizontal (vertical in D. chilensis, sometimes vertical in D. ambrosioides and D. anthelmintica).

Species 14 or 15 (4 in the flora): native to South and Central America (now nearly worldwide from tropics to warm-temperate regions).

Several researchers have treated this section as having a single, highly polymorphic species, Dysphania ambrosioides sensu lato (Chenopodium ambrosioides). Others recognize between two and twelve species (P. Aellen 1929, 1960-1961; P. Aellen and T. Just 1943; V. N. Voroschilov 1942; L. E. Simón 1996, 1997; L. Giusti 1997). We feel that the following four species represent good taxa. There are additional taxa or variations in North America that have not been accounted for here. In particular, the variation in leaf and bract shape and bract size have not been fully recognized. Most of this variation would fall within our concept of D. ambrosioides.