Amaranthus blitum
(livid amaranth)

Preferred Scientific Name

• Amaranthus blitum L. (1753)

Preferred Common Name

• livid amaranth

Other Scientific Names

• Albersia blitum var. oleraceus (L.) Hooker fil. (1885)
• Albersia oleracea (L.) Boiss. (1879)
• Albresia blitum ( L.) Kunth (1838)
• Amaranthus ascendens Loisel. (1810)
• Amaranthus ascendens Loisel. var. oleraceus (L.) Thell. ex Priszter (1953)
• Amaranthus ascendens Loisel. var. polygonoides (Moq.) Thell. (1912)
• Amaranthus ascendens subsp. polygonoides (Moq.) Thell. ex Pr. (1953)
• Amaranthus blitum L. subsp. emarginatus (Moq. ex Uline & Bray) Carretero, Muñoz Garm. y Pedrol
• Amaranthus blitum L. subsp. oleraceus (L.) Costea (2001)
• Amaranthus blitum subsp. polygonoides (Moq.) Carretero (1985)
• Amaranthus blitum var. ascendens (Loisel.) DC (1813)
• Amaranthus emarginatus Moq. ex Uline & Bray (1984)
• Amaranthus emarginatus Salzm. ex Moq. (1849) nom. illeg.
• Amaranthus lividus Hook. f. (1885) nom. illeg.
• Amaranthus lividus L. (1753)
• Amaranthus lividus L. proles oleraceus (L.) Thell. (1914)
• Amaranthus lividus L. proles polygonoides (Moq.) Thell. (1914)
• Amaranthus lividus L. subsp. polygonoides (Moq.) Thell. ex Probst (1949)
• Amaranthus lividus L. var. polygonoides (Moq.) Thell. ex Druce (1920)
• Amaranthus lividus proles ascendens (Loisel.) Thell. (1914)
• Amaranthus lividus proles lividus (Loisel.) Thell. (1914)
• Amaranthus lividus subsp. ascendens (Loisel.) Heukels (1934)
• Amaranthus lividus subsp. oleraceus (L.) Soó (1964)
• Amaranthus oleraceus L. (1763)
• Amaranthus polygonoides Zoll. (1845) nom. illeg.
• Blitum oleraceum (L.) Moench (1794)
• Euxolus ascendens (Loisel.) H. Hara (1938)
• Euxolus blitum (L.) Gren. (1869)
• Euxolus lividus (L.) Moq.,
• Euxolus oleraceus (L.) Moq. (1849)
• Euxolus viridis (L.) Moq. var. ascendens (Loisel.) Moq. (1849)
• Euxolus viridis L. var. polygonoides Moq. (1849)
• Glomeraria livida (L.) Cav. (1803)
• Glomeraria oleracea (L.) Cav. (1803)
• Pixydium oleraceum (L.) Moench (1794)
• Pyxidium lividum (L.) Moench (1794)

International Common Names

• English: pigweed
• Spanish: amaranto ascendente; bledo rojo
• French: amarante livide
• Portuguese: caruru-folha-de-cuia

Local Common Names

• Germany: Amarant (Bleifarbiger); Aufsteigender Amarant; Gruenlicher Amarant; Gruenlicher Fuchsschwanz
• Italy: amaranto livido
• Japan: inubiyu
• Netherlands: kleine majer
• Sweden: maallamarant
• USA: livid amaranth

EPPO code

• AMALI (Amaranthus lividus)

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Caryophyllales
•                         Family: Amaranthaceae
•                             Genus: Amaranthus
•                                 Species: Amaranthus blitum

The nomenclature of A. blitum is somewhat confused, with several Linnean names involved, and needs further molecular and biogeographical study to resolve the taxonomic issues. The names A. blitum and A. lividus L. were both described by Linnaeus (1753), but their use has changed over time, revealing disagreement amongst authors. Townsend (1985, 1988) and Aellen and Akeroyd (1993) used the name A. lividus, but the Committee for Spermatophyta, meeting in 1984 (Taxon, 1984), decided that a choice between the two earliest Linnaean names (A. blitum and A. lividus) should depend on the name selected when they were first combined. As it was Hooker who first combined the two taxa and selected the name A. blitum in 1885, this became the officially preferred name (John Wiersema, USDA, personal communication, 1998). Filias et al. (1980), writing in favour of the use of A. blitum, discussed the issue in detail.

Several infraspecific names of A. blitum have been published, owing to its high phenotypic variability. Townsend (1985, 1988) recognized two subspecies: lividus and polygonoides, on the basis of their somewhat different distributions, the former robust and generally erect, apparently originating in South America and the latter, smaller and generally prostrate, in Europe and Asia. Moquin-Tandon (1849) recognized five varieties (α-ε), three of which (α, δ, ε) now referred to A. graecizans L. Thellung (1914 sub. A. lividus) recognized four subtaxa (named ‘proles’).

Recent comprehensive lists of regional floras have treated differently the varibility of A. blitum, sometimes without recognizing  infraspecific taxa (e.g. Mosyakin and Robertson (2003), in the Flora of North America, or Akeroyd (1993) in Flora Europaea).

Recent detailed morphological investigations (e.g. Costea et al., 2001; Walter and Dobes, 2004) and ongoing studies (Iamonico, in prep.) show that there are three separate taxa that can be distinguished by features of the cotyledons, the leaves, the fruit, the seed sizes, seed surface and pollen pores diameter: A. blitum var. blitum, A. blitum emarginatus and A. blitum oleraceus (see Description). However, their taxonomic ranks remain uncertain.

The subspecies oleraceus is a cultigen form that rarely occurs in the wild in Europe or North America and its native distribution range is not known. Consequently, it could be argued that subsp. oleraceus should not have a taxanomic identity.

The taxa blitum and emarginatus have different origin and Iamonico (personal communication, 2013) suggests that they should be classed as species to reflect their evolutionary histories.

The specific name 'lividus' means 'red' while 'blitum' translates as 'tasteless herb'.

A. blitum is a monoecious annual weed. It grows between 10 and 80 cm tall, sometimes reaching 90 cm.

Stems are prostrate or ascending; sometimes erect, sometimes radiating from base and forming mats; glabrous, green to brown (occasionally reddish), usually highly-branched.

Leaves are usually green, ovate, elliptic to rhombic (see the subspecies descriptions below for the size of the leaves), margins entire, apex emarginate to bilobed (sometimes mucronate), base obtuse or cuneate, glabrous, petioled (petiole 1.0–4.0 cm long).

Synflorescences arranged in axillary glomerules and in terminal spike-like (excepting some forms of the subsp. emarginatus without a terminal spike-like synflorescence), green or brown. Floral bracts, greenwish, ovate [(0.4–)0.8–1.0 by 0.4−0.9 mm], 33-50% shorter than the perianth, acute, margin entire, glabrous. Staminate flowers with 3 tepals, ovate to lanceolate; stamens 3. Pistillate flowers with 3 tepals, lanceolate or linear, elliptic to obovate or spatulate [(0.8−)1.4–1.7(–2.0) by 0.5–1.1(−1.4) mm], with acute apex; stigmas (2−)3.

Pollen grains are small (18–28 μm diameter), have more than 18 uniformly distributed pores (pantoporate), and are covered with granules or spinules, which ensure adherence to the stigma hairs.

Fruit reddish-brown to brown-yellowish, subglobose to elipsoidal (see the subspecies descriptions below for the size of the fruit) as long as or longer than the perianth (in this latter case the length < 2 times of the width), smooth or slightly rugose, indehiscent.

Seed lenticular (see the subspecies descriptions below for diameters), black, brownish-black or dark-reddish, smooth, shiny.

Townsend (1988) indicated that there are more than three perianth segments (0.75 - 2 mm long) mainly in cultivated forms. The capsule is 1.25 - 2.5 mm long. Seeds 1 - 1.75 mm.

The recognized subspecies (blitum, emarginatus and oleraceus) mainly differ each other in cotyledon size, leaf size, fruit length, seed diameter, seed surface and pollen pore diameter. Specifically:

Amaranthus blitum subsp. blitum

Cotyledons with rounded to truncate apex, 9–18 by 3–6 mm; leaf blade size (3.0−)3.5−9.0 by 1.5−6.2 cm; length of the fruit 1.9−3.5 mm; seed diameter 1.1−1.8 mm; seed with minutely punctiform surface and diameter 1.1-1.2 mm; pollen grains with pores of 2.4–3.3 μm.

Amaranthus blitum subsp. emarginatus

Cotyledons with acute apex, 6–7 by 3–6 mm; leaf blade size 1−3.5(−4.5) by (0.5−)0.8−2.5 cm; length of the fruits (1.2−)1.4−1.8(−1.9) mm; seed diameter 0.7−1.1 mm; seed with marginal zone more evidently sculptured; pollen grains with pores of 1.6–1.9 μm.

Amaranthus blitum subsp. oleraceus

Cotyledons with rounded to truncate apex, 9–18 by 3–6 mm; leaf blade size (3.0−)3.5−9.0 by 1.5−6.2 cm; length of the fruit 1.9−3.5 mm; seed diameter 1.1−1.8 mm; seed with smooth surface and diameter 1.2-1.7(-1.9) mm; pollen grains with pores of 2.4–3.3 μm.

The fruits and seeds of A. blitum are able to float and can be dispersed by rain drops or streamlets caused by rain, surface irrigation or water courses.

A. blitum is listed by Holm et al. (1979) as a serious or principal weed in ten countries, mainly across Europe and Asia but also including Nigeria and Mozambique. It occurs in a wide range of field and horticultural crops, grassland, orchards, plantations and vineyards. It appears to be especially troublesome in Japan, where it is one of the three main weeds of warmer upland farms (Takabayashi and Nakayama, 1981), and in the USA. It has become more important in Malaysian plantations with the development of biotypes resistant to paraquat. In Minais Gerais province, Brazil, it is among the five most common weeds of coffee (Laca-Buendia and Brandao, 1994).

It survives passage through the digestive tracts of cattle and may be spread with contaminated dung (Takabayashi et al., 1979). There are also reports of fatal poisoning of cattle following grazing on seedlings of A. blitum (Ferreira et al., 1991).

A. blitum subsp. emarginatus potentially impacts on the native riparian herbaceous vegetation in Europe (Walter and Dobes, 2004).
 

Culinary Uses

A. blitum has been cultivated as a vegetable in Africa, Central and North America (USA and the Caribbean), Asia (China, India, Nepal), Europe (Greece, Italy, Romania) and the South Pacific Islands (Costea et al., 2003). In India it is grown as a leafy vegetable and is known as 'chauli' or 'pokla' (Subbiah and Ramanathan, 1982; Keskar et al., 1983).

The contents of oxalate in leaves (0.08%) and stems (0.15%) increase in plants under stress, but can be reduced by boiling (Abbott and Cambell, 1982).

Nitrate levels in the leaves are equal or superior to spinach (Spinacia oleracea L.). The levels of proteins (22-27%, rich in arginin, tryptophan, isoleucine, and leucine), vitamins (vitamin C and B) and minerals (Ca, Fe, K, Mg, P, S, Al, Zn, Cu) is very high (see Costea et al., 2003). Fibre content is also high.

Its potential as a food crop was reviewed by Turchi (1987).

Medicinal Uses

Fluid extracts are used for throat and mouth ulcers, and due to its astringency, it is recommended for diarrhoea and dysentery (Grieve, 1978). The juice of A. blitum was found to inhibit mutagenesis induced by benzo[a]pyrene, 2-amino-fluorene and 3-amino-1,4 dimethyl-5H-pyridol in Salmonella Typhimurium (Seung et al., 1997).