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| Redroot pigweed - Amaranthus retroflexus L. |
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| Redroot pigweed seedling. |
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| Redroot pigweed seedhead. |
Redroot pigweed stem. |
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Life cycle: Erect summer annual.
Reproduction: Seeds.
Flowers and fruit: Small, greenish flowers are found in dense terminal and axillary clusters of short, thick and prickly spikes. Flowers have bracts two to three times the length of the sepals and yield small, round, shiny black seeds.
Stems: Erect, up to 6-foot-tall herbaceous stems are pale green to reddish and usually nearly red at the base. Lower stems are usually thick, stout and smooth; upper stems are covered with many short, fine hairs.
Leaves: Cotyledons are linear with a prominent midvein and reddish tinted undersides. Leaves are alternate, dull green, egg- to diamond-shaped with a small notch at the tip, smooth to wavy margins and long petioles. Leaves are hairy beneath, at least on the whitish veins. |
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| Redroot pigweed leaf. |
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| Smooth pigweed seedhead. |
Smooth pigweed seedling. |
Smooth pigweed leaf. |
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| Similar weeds: (A. hybridus L.) Differs by having hairless leaves, hairless to slightly hairy upper stems, and seedheads with narrower, less dense and less prickly spikes. |
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| Powell amaranth seedhead. |
Powell Amaranth stem. |
Powell amaranth seedling. |
Powell amaranth leaf. |
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| Similar weeds: Powell amaranth (A. powellii S. Wats.) Differs by having dark green, diamond-shaped, mostly hairless and somewhat glossy leaves; stems with few to no hairs; and seedheads with fewer, very prickly, erect and elongated spikes. |
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