Amaranthus hybridus |
Amaranthus retroflexus |
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slender pigweed, slim amaranth |
redroot amaranth, rough pigweed |
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Habit | Plants mostly glabrous, villous distally when young. | Plants densely to moderately villous, especially in distal portions. |
Stems | erect, branched or not, 3–12(20) dm, green or red. |
erect, 1.5–15(20) dm; simple or branched distally, green or reddish. |
Leaves | blades rhombic-ovate to widely lanceolate; (2)4–12(15) cm, bases wedge-shaped; margins entire; plane; tips acute to obtuse; midveins extending to a spine; petioles 1–5(10) cm. |
blades ovate to rhombic-ovate, 2–15 cm, bases wedge-shaped; margins entire; flat to crisped; midveins extending to a short spine; tips acute to obtuse; petioles 2.5–8 cm. |
Inflorescences | terminal and axillary, tightly clustered; lax and nodding; dull green to red, villous; bracts 2–4 mm; midveins extending to a spine. |
terminal and axillary; erect to somewhat reflexed tightly clustered panicles, green to silvery green; bracts numerous, lanceolate to awl-shaped, 3–6 mm. |
Flowers | perianth segments 5, mostly similar in staminate and pistillate flowers; erect, not overlapping or reflexed, linear to lance-oblong; midveins extending to spine; tips acute. |
perianth segments similar in staminate and pistillate flowers; spoon-shaped to obovate, overlapping, reflexed with age; equal to subequal; midveins extending to a short spine; tips rounded to notched. |
Staminate flowers | generally at inflorescence tips; perianth segments of nearly equal length, 2–3 mm; stamens 5. |
perianth segments 4–5, 2–3 mm; stamens (3)4–5. |
Pistillate flowers | perianth segments of equal length or 1 slightly longer, 1.5–2 mm; styles 3; erect. |
perianth segments 5; (2)2.5–3.5 mm; stigmas 3. |
Fruits | ovoid, 1.5–2.2 mm, rugose at tips; smooth below; dehiscence circumscissile. |
ovoid to elliptic, 1.5–2.5 mm; smooth to rugose at bases; dehiscence usually circumscissile. |
Seeds | lenticular, widely orbicular to rounded, 1–1.4 mm, red-brown to black; shiny. |
lenticular; ovoid to obovoid, 1–1.3 mm, dark brown to black; shiny. |
2n | =32. |
=34. |
Amaranthus hybridus |
Amaranthus retroflexus |
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Distribution | ||
Discussion | Disturbed areas, streambanks, roadsides, fields. Flowering May–Oct. 0–700 m. Casc, Owy, Sisk, WV. CA, ID, NV, WA; throughout North America; scattered worldwide. Native? Amaranthus hybridus has been known to hybridize with A. retroflexus. |
Disturbed areas, fields, roadsides, streambanks. Flowering Jun–Sep. 0–1500 m. BW, Lava, Owy, Sisk, WV. CA, ID, NV, WA; worldwide. Exotic? See also A. hybridus. |
Source | Flora of Oregon, volume 2, page 66 Bridget Chipman |
Flora of Oregon, volume 2, page 66 Bridget Chipman |
Sibling taxa | ||
Web links |
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