West American amaranth

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West American amaranth
American amaranth (Amaranthus blitoides)

American amaranth ( Amaranthus blitoides )

Systematics
Order : Clove-like (Caryophyllales)
Family : Foxtail family (Amaranthaceae)
Subfamily : Amaranthoideae
Genre : Amaranth ( Amaranthus )
Subgenus : Albersia
Type : West American amaranth
Scientific name
Amaranthus blitoides
S. Watson

The West American amaranth or West American foxtail ( Amaranthus blitoides ) is a type of plant from the genus Amaranthus ( Amaranthus ) within the family of the foxtail plants (Amaranthaceae). It is a weed from North America, its common American name is "prostrate pigweed". It is a naturalized neophyte in Europe, South America and other regions . The species occurs very rarely in open ruderal spots and on river banks in Central Europe and is of no economic importance. In contrast to other Amaranthus species, it is not considered "invasive" here.

The leaves have an awn tip and mostly a whitish cartilage edge.
The flowers are clumped in the armpits of leaves.
The fruit is a lid capsule that opens with a transverse crack.
Seeds

description

The West American amaranth is an annual herbaceous plant , the stems of which are prostrate to ascending and richly branched from the base and reach lengths of (0.1 to) 0.2 to 0.6 (to 1) m. The stem is whitish in color, soft and not lignified; it can be hairy on the upper surface or bald. The leaves are stalked, the petiole is about half as long as the dark green leaf blade . This is obovate, elliptical or spatula and measures 1 to 2 (up to 4) × 0.5 to 1 (up to 1.5) cm. The base is wedge-shaped, the edges are usually whole, flat or rarely slightly wavy, with a narrow, white, cartilaginous edge, the tip is blunt to rounded (but not edged) and briefly spiky.

The flowers are separate sexes, but sit on the same plant ( monoecious ) They sit crowded in axillary, ball-shaped inflorescences. The bracts of the female flowers are narrow, thin and 1.5 to 5 mm long, about the same length or slightly longer than the (three to) four to five tepals. These are narrowly ovoid to broadly linear, 1.5 to 3 mm long and more or less unequal, thin and pointed to pointed. The branches of the style stand apart. There are three scars. The male flowers are mixed with the female; they have three (less often four) tepals and three stamens.

The lid capsules, which are torn open regularly, are broadly ovoid, 1.7 to 2.5 mm long as the tepals and mostly smooth, but somewhat warty or wrinkled when dry. The black, rather dull seeds are lenticular to broadly lenticular and have a diameter of 1.3 to 1.6 mm.

The species can be distinguished from the richly shaped Amaranthus blitum by the inflorescence, which is leafy to the tip and not separated, and the leaves that are not edged at the tip. Most other similar species have only two to three flowers (perianth) leaves. All similar species that could be confused are dealt with in Hügin (1987).

The number of chromosomes is 2n = 32.

ecology

The West American foxtail is a summer and fall bloomer; in Central Europe the flowering period extends from July to October. Fertilization occurs mainly through self-pollination, the inconspicuous flowers do not attract pollinators. The seeds do not have any conspicuous means of distribution and, due to their weight, can only be spread a few meters by the wind; they are probably mainly carried away by animals (or by humans); they survive the intestinal passage, germinable seeds could z. B. be detected in the dung of sheep. They can survive for several years and build a permanent seed bank in the soil . The seeds germinate from late spring to late summer (heat germinator), preferably only at temperatures above 25 ° C. The plant blooms and produces fruit in the same year, it is not frost-hardy, the stem shrinks and disintegrates at the first frost.

The West American foxtail is a host species of the parasitic Quendel silk ( Cuscuta epithymum ).

Occurrence

The West American foxtail is widespread in almost all of North America (not, as the common German name would suggest, only in the west). It occurs in the entire USA with the exception of the extreme south (Florida and south of Texas), in Canada only in the southern provinces, where it was probably only introduced when the railroad was built.

The West American foxtail has been introduced almost worldwide to all regions with a subtropical or warm climate. It was brought in to Central Europe, presumably with the transport of goods. Although finds in ports and cotton mills have been around for about 100 years, it was initially only inconsistent. The species has actually only been naturalized since the 1980s, e.g. B. since 1984 in Frankfurt. The distribution map at Floraweb shows evidence of lost property in Germany .

In North America, the West American Foxtail occurs in disturbed locations such as roadsides, river banks, railway lines, fields, fallow land and sandy areas up to an altitude of 2200 m. Starting from railway and port facilities, he settles in similar locations in Central Europe. In the plant-sociological system in Germany it is a species of the association Eragrostio-Amaranthetum blitoidis, which belongs to the association Salsolion ruthenicae and to the order Sisymbrietalia . The West American Foxtail requires nitrogen-rich, not too dry, open soils and is not shade-tolerant.

Systematics

The West American foxtail belongs to the section Blitopsis , a group of inconspicuous, rather similar and difficult to identify amaranth species. The first description as Amaranthus blitoides was in 1877 by Sereno Watson .

A distinction is made between two infraspecific units which, according to American tradition, are regarded as varieties:

  • Amaranthus blitoides var. Blitoides has somewhat fleshy, shorter leaves with a broadly rounded tip.
  • Amaranthus blitoides . Var reverchonii Uline & WLBray contributes somewhat thinner, longer sheets (length to width ratio greater than 2: 1), which are tapered slightly at the end.

Hybrids are known with Amaranthus albus : Amaranthus × budensis , their appearance is between the parents.

Economical meaning

The seeds of Amaranthus blitoides were harvested by the Zuñi people and ground into flour, similar to the more well-known and long-used Kiwicha of South America.

The West American amaranth occurs rarely in fields; it is of relatively little importance as a weed species, but can occur in root crops, under tree crops and in gardens. The species has developed resistance to a number of commercially available herbicides.

swell

Individual evidence

  1. ↑ West American amaranth. In: FloraWeb.de.
  2. ↑ a b Amaranthus blitoides. (No longer available online.) In: Crop Compendium. Bayer Crop Science, archived from the original on October 29, 2013 ; Retrieved October 24, 2013 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.cropscience.bayer.com
  3. ↑ a b D. Bönsel, U. Brunken, T. Gregory, A. Malten, I. Ottich, G. Zizka: Flora of Frankfurt am Main: West American foxtail. Amaranthus blitoides S. Watson. Senckenbergische Naturforschende Gesellschaft, Frankfurt am Main from 2009, PDF file .
  4. ↑ Gerold Hügin: Some remarks on little-known Amaranthus clans (Amaranthaceae) from Central Europe. In: Willdenowia. Volume 16, No. 2, 1987, pp. 453-478, DOI: 10.2307 / 3996513 .
  5. ^ A b c d Mihai Costea, Francois J. Tardif: The Biology of Canadian Weeds. 126. Amaranthus albus L., A. blitoides S. Watson and A. blitum L. In: Canadian Journal of Plant Science. Volume 83, No. 4, 2003, pp. 1039-1066, DOI: 10.4141 / P02-056 .
  6. ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp. 354-355 .
  7. ↑ T. Dimitrova: Check of Amaranthus blitoides W. var. Reverchoni Th. - an element of the control of Cuscuta epithymum Murr in Lucerne (Medicago sativa L.). In: Bulgarian Journal of Agricultural Science. Volume 10, No. 5, 2004, pp. 579-582, abstract .
  8. ↑ MJ Horak, DE Peterson, DJ Chessman, LM Wax: Pigweed Identification. A Pictorial Guide to the Common Pigweeds of the Great Plains. Kansas State University Agricultural Experiment Station and Cooperative Extension Service, Manhattan 1994, PDF file ( Memento of the original from October 29, 2013 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / www.atchison.ksu.edu
  9. ↑ Distribution map for Germany. In: Floraweb .
  10. ↑ Sereno Watson: Descriptions of New Species of Plants, with Revisions of Certain Genera. In: Proceedings of the American Academy of Arts and Sciences. Volume 12, 1877, pp. 246–278 (here: pp. 273 f. )
  11. ↑ Donald B. Pratt, Michael DK Owen, Lynn G. Clark, Anna Gardner: Identification of the weedy pigweeds and waterhemps of Iowa. Iowa State University, Ames 1999, PDF file .

Web links

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