Axyris

Monoecious annuals covered with stellate hairs sometimes intermixed with simple multicellular hairs. Leaves short- or long-petiolate, blade ovate, oblong, spatulate or lanceolate, entire, rarely crisp. Male flowers arranged in terminal spike-like inflorescences up to 8.0 cm long, with minute perianths of 3–5 free hyaline segments and with 2–5 stamens; female flowers located in the bract axils, with five perianth segments. Fruits always dimorphic (heterocarpous); pericarp tightly adjoining the seed coat with small ear-like appendages at the apex of the fruit. Seeds also dimorphic (with thick and thin seed-coat testa). Embryo vertical, horseshoe-shaped or annular; perisperm present. Six species in Eurasia, predominantly in Central Asia; one (A.amaranthoides) is found as an alien plant in many parts of Europe and North America. Fruit morphology and anatomy as well as the peculiarities in plant pubescence are considered the most valuable characters for species delimitation (Sukhorukov 2005, 2011).

Axyris, the Russian pigweeds, are a genus of flowering plants in the amaranth family Amaranthaceae, native to temperate parts of Eastern Europe and Asia. The center of genetic diversity is the Altai to northern Tien-Shan mountains. The best known species is Axyris amaranthoides, which has become a widespread invasive in northern North America.