The alternate leaves have a petiole and a thickish triangular, ovate, rhombic-ovate to lanceolate leaf blade.

The axillary and terminal inflorescences consist of small dense glomerules of flowers, arranged spicately or paniculately.

They contain 5 basally connate perianth segments with a prominent keel near the apex, and a characteristic strong midrib visible from the inside; a circle of 5 stamens; and an ovary with 2 stigmas.

The genus Chenopodiastrum was described in 2012 by Suzy Fuentes-Bazan, Pertti Uotila und Thomas Borsch (in: A novel phylogeny-based generic classification for Chenopodium sensu lato, and a tribal rearrangement of Chenopodioideae (Chenopodiaceae).

After phylogenetic research, this group of species had to be separated from genus Chenopodium, that would otherwise have been polyphyletic.