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  3. Amaranthus spinosus

Amaranthus spinosus

Basic information
Scientific name Amaranthus spinosus (No picture)
Common names Spiny amaranth, Spiny pigweed, Needle burr, Thorny amaranth, Prickly amaranth
Higher taxon Amaranthaceae, Caryophyllales, Magnoliopsida, Magnoliophyta
Natural range North America.
Habitat Farmarea, roadside, etc.
Invasion information
Range in Japan C to W Honshu, Shikoku, Kyushu, Ryukyus, and Ogasawara (Bonin) Islands. Range in Japan
Origin Unknown.
Date Introduced in late 19 C to Ryukyus. Spread in mainland of Japan after W. W. II. Recently spread in northern part of Honshu Is.
Route Accidental: Details unknown.
Impact Competition with native species, crops, pasture, etc. Toxic to domestic animals. Allelopathy. Parasite (insects, nematodes, viruses, etc).
Affected organism: Native plants, crops, domestic animals.
Regulation in Japan No action for prevention, mitigation, control, or eradication.
Introduced range in other countries South America, Africa, Asia, Australia
Reference Notes
  • Ministry of the Environment, Japan. The Invasive Alien Species Act (Accessed on 2011-1-11) http://www.env.go.jp/en/nature/as.html (in Jpn)
  • Osada (1976) Colored Illustrations of Naturalized Plants of Japan. Hoikusha, Osaka (in Jpn)
  • etc.
This species has large genetic variation and hybridizes with other congeners.