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testing weed seeds with water

Testing weed seeds with water

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Date and time: Sun, 06 Mar 2022 03:13:26 GMT

Weed Seed: Amaranthus tuberculatus (Tall water-hemp)

Primary Noxious, Class 2 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.


Worldwide: Native to eastern North America (USDA -ARS 2016 Footnote 3 ) and introduced into Asia (Israel and Jordan), the western United States and Europe (CABI 2016 Footnote 4 ).

Duration of life cycle

Seed or fruit type

Identification features

  • Seed diameter: 0.8 – 1.3 mm


  • Seed is oval or ovate

Surface Texture

  • Seed is glossy, smooth


  • Dark reddish brown

Other Features

  • Hilum is near the top of the seed in a notch.
  • Seeds may have a persistent funiculus at the hilum.
  • The rim around the outside of the seed, common in Amaranthusspp. is diminished or lacking in this species.

Habitat and Crop Association

Cultivated fields, wet areas, including the margins of ponds, rivers and ditches, roadsides, and disturbed areas (Darbyshire 2003 Footnote 2 , FNA 1993+ Footnote 5 ). A dominant weed of soybean and corn fields in the United States (Costea et al. 2005 Footnote 6 ).

General Information

Tall water-hemp produces 35,000-1,200,000 seeds per plant and forms persistent seed banks under cultivation (Costea et al. 2005 Footnote 6 ).

See also  buy weed seeds dc

This species prefers warm, moderately moist, nitrogen-rich sites in full sunlight (Costea et al. 2005 Footnote 6 ). Considering that both seed and fruits float and the species prefers to grow near water, (Costea et al. 2005 Footnote 6 ) suggest that dispersal by water may be significant.

Similar species

Redroot pigweed (Amaranthus retroflexus)

  • Redroot pigweed seed has a similar lenticular shape, notched hilum and glossy surface as tall water-hemp.
  • Redroot pigweed seed is larger by up to 0.5 mm , has a pronounced rim, and is black.
  • Tall water-hemp seeds do not have a rim and are reddish-brown.


Similar species


Brouillet, L., Coursol, F., Favreau, M. and Anions, M. 2016. VASCAN, the database vascular plants of Canada, [2016, May 30].

Darbyshire, S. J. 2003. Inventory of Canadian Agricultural Weeds. Agriculture and Agri-Food Canada, Research Branch. Ottawa, ON .

Costea, M., Weaver, S. E. and Tardif, F. J. 2005. The Biology of Invasive Alien Plants in Canada. 3. Amaranthus tuberculatus (Moq.) Sauer var. rudis (Sauer) Costea & Tardif. Canadian Journal of Plant Science 85: 507-522.