Weed Information: Amaranthus viridis (amaranth, slender)
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Amaranthus viridis (amaranth, slender)

Family: Amaranthaceae

Description

Similar in general appearance to spiny pigweed but without spines at the nodes. The fruit is strongly roughened and the spiny bracts subtending the flowers are shorter than the flowers.

Characteristics

Flower Color
  • Green
Inflorescence Type (How the flowers are arranged on the plant)
  • Axillary spikes
  • Panicle
  • Terminal spike
Number of Petals
  • 0 (no petals)
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • < 1 mm (< .04 inch)
  • 1 mm (.04 inch)
  • 2 mm (.08 inch)
Flower Width (Head width in the Asteraceae)
  • < 1 mm (< .04 inch)
  • 1 mm (.04 inch)
  • 2 mm (.08 inch)
Number of Sepals
  • 3 sepals
  • 5 sepals
Sepal Separation
  • Completely free to base
Sepal Tip
  • Pointed
Flower Sex
  • Unisexual (monoecious or dioecious)
Number of Styles
  • Styles lacking (male flowers only)
  • 1 style
Number of Stamens
  • stamens lacking (female flowers only)
  • 2 stamens
  • 3 stamens
Stamens Attached to the Petals
  • Stamens NOT attached to the petals
Stamens Connate (united)
  • Filaments or anthers NOT united

Carpel Separation
  • Carpels united (or one)
Number of Carpels
  • 0 (male flowers only or plants producing spores)
  • 2 carpels
  • 3 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Utricle
Fruit Length at Maturity
  • 1 mm (.04 inch) or less
  • 2 mm (.08 inch)
Fruit Width at Maturity
  • 1 mm (.04 inch) or less
Burs
  • Fruit or seed NOT bur-like

Leaf Arrangement
  • Alternate
Leaf Type
  • Simple (including lobed leaves)
Stipules
  • Lacking
Tendrils
  • Tendrils absent
Venation
  • Pinnate
Petiole (leaf stem) Blade Ratio
  • Petiole < 25% total length
  • Petiole 25% - 75% total length
Leaf Length (blade PLUS petiole)
  • 2 - 4 cm (.80 - 1.60 inches)
  • 4 - 10 cm (1.60 - 4.0 inches)
Leaf Width
  • 1 - 2 cm (.40 - .80 inch)
  • 2 - 4 cm (.80 - 1.6 inches)
Leaf Shape (simple leaves only)
  • Elliptic
  • Obovate
  • Orbicular (round)
  • Oval
  • Ovate
Leaf or Leaflet Margin
  • Entire
  • Undulate (sinuate, repand)
Leaf or Leaflet Blade Base
  • Acute (cuneate)
  • Rounded
Leaf or Leaflet Tip
  • Notched (emarginate, retuse)
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Glabrous (NO hairs)
  • Sparsely hairy
Succulence
  • Not succulent

Milky Juice
  • Juice NOT milky (watery)
Woodiness
  • Herbaceous
Spines or Thorns
  • Spines or Thorns ABSENT
  • Spines on flowers or fruits only
Aromatic (vegetative structures)
  • Not aromatic
Life Cycle
  • Annual
Growth Habit (while flowering)
  • Erect, columnar (narrow)
  • Erect, spherical (bushy)
Plant Height at Maturity
  • 4 - 6 dm (1.3 - 2.0 feet)
  • 6 - 8 dm (2.0 - 2.6 feet)
  • 8 - 10 dm (2.6 - 3.3 feet)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Mesic
Chlorophyll
  • Present

Stem Cross Section
  • Ridged
  • Round
Flowering Stem Leaves
  • Stem uniformly leafy
Main Stem Branches
  • Main stem branched

Root or Vegetative Propagule
  • Tap Root

US State
  • Alabama
  • Arkansas
  • Florida
  • Georgia
  • Louisiana
  • Massachusetts
  • Michigan
  • Missouri
  • Mississippi
  • North Carolina
  • New York
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • Wisconsin
  • Hawaii
  • Arizona
  • California
  • New Mexico
  • Oklahoma
Other
  • Virgin Islands

  • S.W.S.S. Weed ID Guide, 1993 Section Number and Five letter code: 3 AMAVI
  • Weeds of Southern Turfgrasses, 1992 Univ. of Florida, Gainesville Publication # SP-79, See page: 73
  • Weeds of the South, University of Georgia 2009, ISBN#0-8203-3046-9 See page: 38
  • Listed as a `Weed` by the Biota of North America Program, 2008 X
  • Listed in the WSSA Composite List of Weeds X
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