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Species
Amaranthus retroflexus L. (1753)
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Distribution: A native of N. America south to N. Mexico; introduced into the Old World as a weed, but in more temperate regions than many of its allies, occurring in S. and C. Europe, Mediterranean N. Africa and temperate Asia from Cyprus and Turkey to Iran, Siberia, Middle Asia, Mongolia, China and Japan. Also adventive in Australia and S. America (Bolivia etc.) and probably elsewhere. Generally occurs as a weed of cultivation, occurring as such in the cooler parts of Pakistan, ascending to 1820 m or more.
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More info on this topic.
More info for the term: therophyte
Therophyte
Rough pigweed seeds with hulls contain 18.0 percent protein [29].
The nutritional components of immature rough pigweed browse are [29]:
Component Percent
Ash 18.8
Crude Fiber 10.8
N-free Extract 43.2
Protein 25.7
The use that various animals can make of protein in rough pigweed browse
is [29]:
Percent
Animal Digestible Protein
Cattle 19.7
Goats 20.5
Horses 19.3
Rabbits 18.5
Sheep 20.9
The food value of rough pigweed for wildlife species in several western
states is rated as follows [7]:
North
Dakota Utah Wyoming
Pronghorn good fair poor
Elk fair poor
Mule deer good good poor
White-tailed deer good poor
Small Mammals fair good
Small nongame birds good good
Upland game birds good fair good
Waterfowl good poor fair
In Minnesota, rough pigweed harvested from late June to mid-July showed
a nutrient composition and digestibility for sheep equivalent to that of
high-quality alfalfa (Medicago sativa). Rough pigweed contained
adequate minerals to meet the requirements of ruminants. However, it
must be utilized at relatively early stages of maturity. Nitrate
concentration, which has been implicated in livestock poisoning, is
highest in rough pigweed just before bloom. Calcium to potassium ratio
in rough pigweed is such that it should not be fed as the sole ration
[25].
More info for the term: monoecious
Rough pigweed is an introduced, coarse, monoecious, annual herb with
taproots. It has an erect stem, 1 to 6.6 feet (0.3-2 m) tall, that is
commonly freely branched. Leaves are 0.8 to 3.9 inches (2-10 cm) long.
Inflorescences are usually densely crowded. There are often additional
dense clusters of flowers in the axils of upper leaves. The fruit is a
utricle [11,14,18,19,34].
Rough pigweed has a taproot. In pinyon-juniper (Pinus-Juniperus)
woodland in New Mexico, root depth averaged 39 inches (100 cm), with a
range of 3.9 to 95 inches (10-240 cm) [12].
More info for the term: forb
Forb
Rough pigweed is probably unpalatable when mature because of the stiff,
spine-like bracts in the flower clusters.
In Utah, rough pigweed was rated as having fair palatability for cattle
and horses, and good palatability for sheep [7].
In Minnesota, rough pigweed was as palatable to sheep as oats (Avena
sativa) [25].
Annual herb, erect or with ascending branches, (6-) 15-80 (-100) cm, simple or branched (especially from the base to about the middle of the stem). Stem stout, sub-terete to angled, densely furnished with multicellular hairs. Leaves furnished with multicellular hairs along the lower surface of the primary venation and often the lower margins, long-petiolate (petioles up to c. 6 cm, in robust plants not rarely equalling the lamina), lamina ovate to rhomboid or oblong-ovate, (1-) 5-11 x (0.6-) 3-6 cm, obtuse to subacute at the mucronulate tip, shortly cuneate or attenuate into the petiole. Flowers in greenish or rarely somewhat pink-suffused, stout, axillary and terminal spikes, which are usually shortly branched to give a lobed appearance, more rarely with longer branches, the terminal inflorescence paniculate, very variable in size, male and female flowers intermixed, the latter generally much more plentiful except sometimes at the tip of the spikes. Bracts and bracteoles lanceolate-subulate, pale-membranous with a prominent green midrib excurrent into a stiff, colourless arista, longer bracteoles subequalling to twice as long as the perianth. Perianth segments 5, those of the male flowers 1.75-2.25 mm, lanceolate-oblong, blunt to subacute, those of the female flowers 2-3 mm, narrowly oblong-spathulate to spathulate, obtuse or emarginate, ± green-vittate along the midrib, which ceases below the apex or is excurrent in a short mucro. Stigmas 2-3, patent-flexuose or erect, c. 1 mm. Capsule subglobose, c. 2 mm, usually shorter than the perianth, circumscissile, with an indistinct neck, rugose below the lid. Seed black and shining, compressed, c. 1 mm, almost smooth centrally, faintly reticulate around the margins.
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Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=200006986 |
Ground residual colonizer (on-site, initial community)
Initial-offsite colonizer (off-site, initial community)
Amaranthus retroflexus is a species of flowering plant in the Amaranthaceae family with several common names, including red-root amaranth, redroot pigweed, red-rooted pigweed, common amaranth, pigweed amaranth, and common tumbleweed.[3]
Description[edit]
Amaranthus retroflexus, true to one of its common names, forms a tumbleweed.[3] It is native to the tropical Americas, but is widespread as an introduced species on most continents in a great number of habitats. This is an erect, annual herb reaching a maximum height near 3 metres (9.8 ft). The leaves are nearly 15 centimetres (5.9 in) long on large individuals, the ones higher on the stem having a lance shape and those lower on the plant diamond or oval in shape. The plant is monoecious, with individuals bearing both male and female flowers. The inflorescence is a large, dense cluster of flowers interspersed with spiny green bracts. The fruit is a capsule less than 2 millimetres (0.079 in) long with a "lid" which opens to reveal a tiny black seed. Another of A. retroflexus's common names, pigweed, stems from the fact that it grows where hogs are pasture-fed.
Culinary use[edit]
This plant is eaten as a vegetable in different places of the world. No species of genus Amaranthus is known to be poisonous,[4] but the leaves contain oxalic acid and may contain nitrates if grown in nitrate-rich soils, so the water should be discarded after boiling.
A. retroflexus was used for a multitude of food and medicinal purposes by many Native American groups.[5]
It is used in the Indian state of Kerala to prepare a popular dish known as thoran by combining the finely cut leaves with grated coconut, chili peppers, garlic, turmeric and other ingredients.
The seeds are edible raw or toasted, and can be ground into flour and used for bread, hot cereal, or as a thickener.[6]
Use as fodder[edit]
Like many other species of Amaranthus, this plant may be harmful and even deadly when fed to cattle and pigs in large amounts over several days. Such forage may cause fatal nephrotoxicity,[7] presumably because of its high oxalate content. Other symptoms, such as bloat, might reflect its high nitrate content.[8] However, when supplied in moderation, it is regarded as an exceptionally nutritious fodder.[9]
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Source | http://en.wikipedia.org/w/index.php?title=Amaranthus_retroflexus&oldid=648376107 |
Stem erect, light green, 20-80 cm tall, stout, branched or not, slightly obtusely angulate, densely pubescent. Petiole light green, 1.5-5.5 cm, hairy; leaf blade ovate-rhombic or elliptic, 5-12 × 2-5 cm, both surfaces shortly hairy, but densely hairy abaxially, base cuneate, margin entire and undulate, apex acute or notched, with a mucro. Complex thyrsoid structures terminal and axillary, erect, 2-4 cm in diam., including many spikes; terminal spikes longer than lateral ones. Bracts and bracteoles white, subulate, 4-6 mm, apex slenderly long pointed. Tepals white, oblong or oblong-obovate, 2-2.5 mm, membranous, with a green midvein, apex acute or notched, with a mucro. Stamens slightly longer than perianth. Stigmas 3, rarely 2. Utricles light green, ovoid, compressed, shorter than perianth, circumscissile. Seeds brown or black, subglobose, ca. 1 mm in diam., obtuse at margin. Fl. Jul-Aug, fr. Aug-Sep. 2n = 32*, 34*, 102*.
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200006986 |