Amaranthaceae



         


family of dicotyledons, included among the Caryophyllales. Notable members include amaranth and tumbleweeds.

This is a widespread and cosmopolitan family of herbs and shrubs, occurring in temperate, subtropical and tropical regions. The tropical species occur mainly in Africa and America. They are only occasionally climbers.

The leaves are entire, opposite or alternate, without stipules. In most cases, there are neither basal or terminal aggregations of leaves.

The flowers are solitary or aggregated in cymes, spikes or heads. Most plants are hermaphrodite or monoecious. 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 a berry, a drupe, a capsule or a nut.

Most species are weeds, but some are popular ornamentals, especially species from Alternanthera, Amaranthus, Celosia and Iresine.

Newer classifications, such as the update of the Angiosperm Phylogeny Group, include the former family Chenopodiaceae in the Amaranth family. Well-known species are goosefoot, quinoa, beets, and spinach.

The main differences with the Chenopodiaceae are the membraneous petals and the stamens, often united in a ring structure.

Most Chenopodiaceae are halophytes, i.e. growing naturally in salty soils. Since such soils are often dry, many show xerophytic forms, i.e. are adapted to dry soils. Therefore many have deep roots, such as beets. The exstipulate leaves are small to large, glabrous, hairy or mealy. The margins can be entire, lobate or toothed. Species of Salicornia even lack leaves and have club-shaped stems, giving them a cactus-like appearance. The flowers in this family are minute, arranged in spikes or cymes. In some species they are solitary and axillary.

Without the Chenopodiaceae, there are about 65 genera and about 900 species in the family; with them, about 160 genera and about 2400 species.

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Genera of Amaranthaceae


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Genera of Chenopodiaceae







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