Powell's Amaranth (Amaranthus powellii) is an annual herbaceous flowering plant in the amaranth family (Amaranthaceae), native to the southwestern United States and northwestern Mexico. It is a member of the genus Amaranthus, which includes approximately 70 species of cosmopolitan annual or short-lived perennial plants, several of which are important grain and leafy vegetable crops. Powell's Amaranth is considered a weedy species in many regions where it has been introduced, often found as an agricultural weed, but it shares the same nutritional qualities that have made amaranth a valued food crop for millennia.
• Has been introduced widely across North America, Europe, parts of Asia, and other temperate and subtropical regions
• Commonly naturalized as a weed in disturbed habitats, agricultural fields, roadsides, and waste areas
• The genus Amaranthus has a complex biogeographical history, with centers of diversity in the Americas and secondary centers in tropical Asia and Africa
• Several amaranth species were staple grain crops of pre-Columbian civilizations; Aztec cultures cultivated Amaranthus hypochondriacus extensively
Stem:
• Erect, stout, branching, often somewhat ridged
• Green to reddish in color, glabrous to sparsely pubescent
Leaves:
• Alternate, simple, with long petioles (2–10 cm)
• Blade broadly ovate to rhombic-ovate, 3–12 cm long, 2–7 cm wide
• Margin entire; apex obtuse to acute; base cuneate
• Glabrous or nearly so on both surfaces
Inflorescence:
• Dense terminal and axillary spikes, often thick and clustered
• Spikes greenish, 3–10 cm long, with bracts longer than the perianth (a key distinguishing feature from some related species)
• Bracts conspicuously awn-tipped, ovate, about twice the length of the perianth
Flowers:
• Unisexual (plants monoecious — male and female flowers on the same individual)
• Perianth segments 5, oblong, with prominent midribs
• Male flowers with 5 stamens; female flowers with a single pistil and 3 stigmas
Fruit & Seeds:
• Utricle (a small, thin-walled, single-seeded fruit) circumscissile (splitting around the middle at maturity)
• Seeds small (~1–1.5 mm diameter), lenticular (lens-shaped), dark brown to black, glossy
• A single plant can produce tens of thousands of seeds, contributing to its weedy persistence
Roots:
• Fibrous root system, sometimes with a slightly thickened taproot
Habitat:
• Agricultural fields, gardens, roadsides, ditches, disturbed lots, and waste ground
• Prefers full sun and well-drained soils
• Tolerates a range of soil types including sandy, loamy, and clay soils
• Commonly found at elevations from sea level to approximately 1,500 m
Phenology:
• Germinates in late spring to early summer when soil temperatures are warm
• Flowers from mid-summer through autumn
• Produces seed prolifically from late summer until frost
Ecological Interactions:
• Seeds are an important food source for granivorous birds and small mammals
• Pollinated by wind (anemophilous)
• High seed output and ability to germinate over an extended period contribute to persistent soil seed banks
• Can act as a host for certain agricultural pests and pathogens
Growth Conditions:
• Full sun preferred; does not tolerate shade
• Adaptable to a wide range of soil types (sandy, loamy, clay)
• Tolerant of moderate drought once established
• Prefers warm temperatures; frost-sensitive
Germination & Growth:
• Seeds germinate best at soil temperatures of 18–30°C
• Rapid growth rate under favorable conditions
• Can complete its life cycle (seed to seed) in approximately 60–90 days
Weed Management:
• Manual removal before seed set is effective for small infestations
• Mulching and dense crop canopy can suppress germination
• Herbicide resistance has been documented in some Amaranthus species; integrated management is recommended
• As a C4 plant, it is highly efficient at photosynthesis in hot, sunny conditions, giving it a competitive advantage in summer crops
Wusstest du schon?
Powell's Amaranth belongs to one of the most nutritionally remarkable plant groups on Earth. Amaranth grains are considered a "pseudocereal" — they are not true cereal grasses (Poaceae) but produce starchy seeds used in much the same way as wheat or rice. • Amaranth seeds contain approximately 13–18% protein by weight, higher than most true cereals • They are notably rich in the essential amino acid lysine, which is typically limiting in wheat, rice, and maize — making amaranth a nutritionally complementary grain • The seeds are naturally gluten-free, which has driven renewed interest in amaranth as a health food in recent decades • Amaranth was a staple of Aztec civilization; it was so culturally significant that it was used in religious ceremonies involving shaped dough figures, which Spanish colonial authorities attempted to suppress The genus Amaranthus includes species classified as among the world's most problematic agricultural weeds: • Several amaranth species, including Amaranthus palmeri (Palmer amaranth), have evolved resistance to multiple herbicide classes including glyphosate • Palmer amaranth is considered one of the most economically damaging weeds in United States agriculture, capable of reducing soybean yields by up to 79% if left uncontrolled • Amaranthus species are among the few plants that use the C4 photosynthetic pathway, giving them exceptional water-use efficiency and growth rates under hot, sunny conditions The C4 Advantage: • C4 photosynthesis is an evolutionary adaptation that concentrates CO2 around the enzyme RuBisCO, minimizing wasteful photorespiration • This allows amaranth and other C4 plants to photosynthesize more efficiently at high temperatures and light intensities • C4 plants lose roughly half as much water per unit of carbon fixed compared to C3 plants, contributing to their success as summer weeds in agricultural settings
Mehr erfahrenKommentare (0)
Noch keine Kommentare. Schreiben Sie den ersten!
