''Amaranthus retroflexus'' is a species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the family

Amaranthaceae Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus ''Amaranthus''. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it ...

with several common names, including red-root amaranth, redroot pigweed, red-rooted pigweed, common amaranth, pigweed amaranth, and common tumbleweed. page 470

Description

''Amaranthus retroflexus,'' true to one of its common names, forms a

tumbleweed A tumbleweed is a structural part of the above-ground anatomy of a number of species of plants. It is a diaspore that, once mature and dry, detaches from its root or stem and rolls due to the force of the wind. In most such species, the tumbl ...

. It is native to the tropical Americas, but is widespread as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

on most continents in a great number of habitats. This is an erect, annual herb reaching a maximum height near . The leaves are nearly long on large individuals, the ones higher on the stem having a lance shape and those lower on the plant diamond or oval in shape. The plant is monoecious, with individuals bearing both male and female flowers. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

is a large, dense cluster of flowers interspersed with spiny green bracts. The fruit is a capsule less than long with a "lid" which opens to reveal a tiny black seed. Another of ''A. retroflexus's'' common names is "pigweed" because it grows where hogs are pasture-fed.

Culinary use

This plant is eaten as a vegetable in different places of the world. No species of genus ''Amaranthus'' is known to be poisonous, but the leaves contain oxalic acid and may contain nitrates if grown in nitrate-rich soils, so the water should be discarded after boiling. The young shoots and leaves can be eaten raw. The leaves are high in calcium, iron, protein, and

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

. ''A. retroflexus'' was used for a multitude of food and medicinal purposes by many Native American groups in the US West. It is among the species consumed as a vegetable in Mexican markets as ''Quelite quintonil''. It is used in the

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

n state of

Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South ...

to prepare a popular dish known as ''

thoran Thoran ( ml, തോരൻ, pronounced ; or upperi in Northern Kerala is a class of dry vegetable dishes combined with coconut that originated in the Indian state of Kerala. This common dish is usually eaten with rice and curry and is also par ...

'' by combining the finely cut leaves with grated coconut,

chili pepper Chili peppers (also chile, chile pepper, chilli pepper, or chilli), from Nahuatl '' chīlli'' (), are varieties of the berry-fruit of plants from the genus ''Capsicum'', which are members of the nightshade family Solanaceae, cultivated for ...

s, garlic,

turmeric Turmeric () is a flowering plant, ''Curcuma longa'' (), of the ginger family, Zingiberaceae, the rhizomes of which are used in cooking. The plant is a perennial, rhizomatous, herbaceous plant native to the Indian subcontinent and Southeast ...

and other ingredients. The seeds are edible raw or toasted, and can be ground into flour and used for bread, hot cereal, or as a thickener.

Use as fodder

Like many other species of ''Amaranthus'', this plant may be harmful and even deadly when fed to

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult ma ...

and

pig The pig (''Sus domesticus''), often called swine, hog, or domestic pig when distinguishing from other members of the genus '' Sus'', is an omnivorous, domesticated, even-toed, hoofed mammal. It is variously considered a subspecies of ''Sus ...

s in large amounts over several days. Such forage may cause fatal

nephrotoxicity Nephrotoxicity is toxicity in the kidneys. It is a poisonous effect of some substances, both toxic chemicals and medications, on kidney function. There are various forms, and some drugs may affect kidney function in more than one way. Nephrotoxins ...

,FEIS Ecology
/ref> presumably because of its high oxalate content. Other symptoms, such as bloat or methylglobineamia in the most severe cases, might reflect its high nitrate content. However, when supplied in moderation, it is regarded as an exceptionally nutritious fodder.Watt, John Mitchell; Breyer-Brandwijk, Maria Gerdina: The Medicinal and Poisonous Plants of Southern and Eastern Africa 2nd ed Pub. E & S Livingstone 1962

As a weed

''A. retroflexus'' is a

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

and has developed resistance against

fomesafen Fomesafen is the ISO common name for an organic compound used as an herbicide. It acts by inhibiting the enzyme protoporphyrinogen oxidase which is necessary for chlorophyll synthesis. Soybeans naturally have a high tolerance to fomesafen, via ...

Northeast China Northeast China or Northeastern China () is a geographical region of China, which is often referred to as "Manchuria" or "Inner Manchuria" by surrounding countries and the West. It usually corresponds specifically to the three provinces east of ...

References

External links

*
Jepson Manual Treatment
*
Amaranthus retroflexus L.
Medicinal Plant Images Database (School of Chinese Medicine, Hong Kong Baptist University) * {{Taxonbar, from=Q157663 retroflexus Flora of North America Flora of South America Plants described in 1753 Taxa named by Carl Linnaeus Kerala cuisine Plants used in Native American cuisine Invasive plant species in Japan