Vernacular
  • doringmisbredie,
  • mohwa-guru,
  • Needle burr,
  • prickly careless weed,
  • sere pelêlê,
  • Soldier weed,
  • Spiny amaranth,
  • Spiny pigweed,
  • Spring pigweed,
  • Thorny amaranth,
  • Thorny pigweed
Details
Eppo_code

AMASP

Family

Amaranthaceae

Species

Amaranthus spinosus L.

Meaning_of_the_name

Amaranthus - derives from the greek word "amarantos" meaning immortal or unfading and "anthos" meaning flower, and refers to long lasting qualities of of the flower; spinosus: spiny.

Global_description

Amaranthus spinosus is an erect, many-branched annual herb growing up to 1.5 m. The stem is smooth, robust, cylindrical and often reddish. The leaves are simple and alternate, glabrous or with sparse hairs on the main veins below, often diamond-shaped, long petiolate, up to 9 cm. They are dotted with numerous translucid spots; the venation is well marked. The leaf axils bear pairs of fine and slender spines. The small green flowers are grouped in clusters in the axils of the leaves and in branched terminal spikes. The fruit is a dehiscent capsule that splits open at maturity (dehiscent); it contains a single smooth, black, lens-shaped seed.

Similar_species

Can be confused with several other species in the family Amaranthaceae.

Cotyledons

Cotyledones are linear to lanceolate, usually red to purple underneath, 10 mm long and 2 mm wide.

First_leaves

Long-stalked, simple and alternate. The lamina is obovate shaped for the first 2 or 3 leaves, then elliptical or oval for the following leaves. Apices are mucronate and the lower surfaces are usually purple.

Habit

An upright, erect annual herb, many branched. Grows up to 1 m high.

Underground_system

Taproot.

Stem

Cylindrical and smooth, it can be green or red. A pair of strong spines, reddish and swollen, are inserted at the base of the leaf stalk (petiole).

Leaves

Leaves are simple and alternate. The lamina is oval, 5 to 10 cm long and 2 to 5 cm wide. The apex is deeply notched. The margin is entire. Each leaf has 8 to 10 slightly curved lateral veins that are clearly visible below. Both sides are smooth, with many small translucent dots. The upper side is green, the lower side often purple.

Inflorescence

Flowers are grouped in sessile clusters, arranged into spikes at the tip of thick branches, or in glomeruli in the axils of the leaves.

Flowers

The flowers are very small and green, unisexual. They have no petals but five scarious sepals. The female flowers are located at the base of the spikes, the male flowers at the tip. Male flowers have five stamens.

Fruits

Capsule ovoid , 2 mm x 1 mm, splitting along a transverse circular line (circumscissile) at maturity, one-seeded.

Seeds

Seeds are lenticular, smooth, shiny, reddish brown, 0.8 mm in diameter.

Biology

A. spinosus is an annual weed. It reproduces by seeds. The seeds are spread by water and wind.

Ecology

It occurs on roadsides, villages, disturbed areas, along the livestock holding areas. It is a weed of crops. It prefers rich soil in organic matter and nitrogen.

Origine

Native to tropical America.

World_distribution
South_african_distribution
Knp_distribution
Use

It is traditionally used to treat chest.

Global_weediness
South_african_weediness
Knp_weediness
Global_control
Control_knp
References

Grard, P., T. Le Bourgeois and H. Merlier (2010). Adventrop V.1.5 Les adventices d'Afrique soudano-sahélienne. Cirad, Montpellier, France.
Le Bourgeois, T., A. Carrara, M. Dodet, W. Dogley, A. Gaungoo, P. Grard, Y. Ibrahim, E. Jeuffrault, G. Lebreton, P. Poilecot, J. Prosperi, J. A. Randriamampianina, A. P. Andrianaivo and F. Théveny (2008). Advent-OI : Principales adventices des îles du sud-ouest de l'Océan Indien. Cirad. Montpellier, France.
-Australian Tropical Rainforest Plants
-Bromilow C. 2010. Problem plants and alien weeds of South Africa. Pretoria: Briza Publications. p. 206.
- Hyde, M.A., Wursten, B.T. & Ballings, P. (2013). Flora of Zimbabwe: Species information: Amaranthus spinosus.
-Pacific Island Ecosystems at Risk (PIER)
-Swaziland’s Alien Plants Database

Web_links

http://idao.cirad.fr/SpecieSheet?sheet=adventoi/especes/a/amasp/amasp_fr.html
http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=122210
http://www.sntc.org.sz/alienplants/speciesinfo.asp?spid=34
http://www.hear.org/pier/species/amaranthus_spinosus.htm
http://keys.trin.org.au/key-server/data/0e0f0504-0103-430d-8004-060d07080d04/media/Html/taxon/Amaranthus_spinosus.htm

Vernacular Country Language Source
Spiny amaranth English R.P.Randall, 2002
mohwa-guru Shona Bromilow C. 2010. Problem plants and alien weeds of South Africa
sere pelêlê Pedi Bromilow C. 2010. Problem plants and alien weeds of South Africa
Spring pigweed English R.P.Randall, 2002
prickly careless weed English Bromilow C. 2010. Problem plants and alien weeds of South Africa
doringmisbredie Afrikaans Bromilow C. 2010. Problem plants and alien weeds of South Africa
Thorny amaranth English Tropicos
Spiny pigweed English R.P.Randall, 2002
Thorny pigweed English Foxcroft, 2003
Soldier weed English Tropicos
Needle burr English R.P.Randall, 2002
Map