Amaranthoideae
Chenopodioideae
Gomphrenoideae
Salicornioideae
Salsoloideae
The family Amaranthaceae, the Amaranth family, is a taxon of dicotyledon flowering plants included among the Caryophyllales and containing about 65 genera and 900 species. Most of these species are herbs or subshrubs; very few are trees or climbers. This is a widespread and cosmopolitan family found mostly in subtropical and tropical regions, yet a few species are native to cool temperate regions. Most species occur in tropical Africa and North America. Some species are considered weeds, but a number of others are popular garden ornamentals, especially species from Alternanthera, Amaranthus, Celosia, and Iresine .
Notable members include amaranth and tumbleweeds.
The leaves are simple, margins entire, opposite or alternate, and without stipules. In most cases, there are neither basal or terminal aggregations of leaves. The flowers are solitary or aggregated in cymes, spikes, or panicles and typically perfect (bisexual) and actinomorphic. A few species have unisexual flowers. The bracteate flowers are regular with 4 to 5 petals, often joined. There are 1 to 5 stamens. The hypogynous ovary has 3 to 5 joined sepals. The fruit can be an utricle, nut, or circumscissile capsule, rarely a berry.
Newer classification schemes, such as the update of the Angiosperm Phylogeny Group, include the family Chenopodiaceae in the Amaranth family. Well-known species of chenopodes are goosefoot, quinoa, beet, and spinach. The main differences between Amaranthaceae and Chenopodiaceae are membraneous petals and stamens often united in a ring structure. Incorporating the Chenopodiaceae brings the number of genera to about 160 and the number of species to about 2400.
Most Chenopodiaceae are halophytes, i.e. grow in salty soils.
