- Needle burr,
- prickly careless weed,
- sere pelêlê,
- Soldier weed,
- Spiny amaranth,
- Spiny pigweed,
- Spring pigweed,
- Thorny amaranth,
- Thorny pigweed
Amaranthus spinosus L.
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.
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.
Can be confused with several other species in the family Amaranthaceae.
Cotyledones are linear to lanceolate, usually red to purple underneath, 10 mm long and 2 mm wide.
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.
An upright, erect annual herb, many branched. Grows up to 1 m high.
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 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.
Flowers are grouped in sessile clusters, arranged into spikes at the tip of thick branches, or in glomeruli in the axils of the leaves.
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.
Capsule ovoid , 2 mm x 1 mm, splitting along a transverse circular line (circumscissile) at maturity, one-seeded.
Seeds are lenticular, smooth, shiny, reddish brown, 0.8 mm in diameter.
A. spinosus is an annual weed. It reproduces by seeds. The seeds are spread by water and wind.
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.
Native to tropical America.
It is traditionally used to treat chest.
Grard, P., T. Le Bourgeois and H. Merlier (2010). Adventrop V.1.5 Les adventices d'Afrique soudano-sahélienne. Cirad, Montpellier, France.
|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|
|Spiny pigweed||English||R.P.Randall, 2002|
|Thorny pigweed||English||Foxcroft, 2003|
|Needle burr||English||R.P.Randall, 2002|