Weed Information: Mentzelia nuda (mentzelia, naked)
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Mentzelia nuda (mentzelia, naked)

Family: Loasaceae

Description

Very similar to Mentzelia decapetala but generally more delicate. The flowers are usually white and the plants often occur on sandy soils. Native to most of the Great Plains.

Characteristics

Flower Color
  • Yellow
  • White
Inflorescence Type (How the flowers are arranged on the plant)
  • Cyme (simple or branched)
Number of Petals
  • 10 petals
Petal Separation
  • Completely free to base
Petal Tip
  • Pointed
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.6 inch)
  • 2.0 cm (.8 inch)
  • 2.5 cm (1.0 inch)
  • 3.0 cm (1.2 inches)
Flower Width (Head width in the Asteraceae)
  • 4.0 cm (1.6 inches)
  • 4.5 cm (1.8 inches)
  • 5.0 cm (2.0 inches)
  • > 5.0 cm (> 2.0 inches)
Number of Sepals
  • 5 sepals
Sepal Separation
  • Completely free to base
Sepal Tip
  • Pointed
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • 1 style
Number of Stamens
  • more than 10 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
  • 1 carpel
Ovary Position
  • Inferior (epigynous)
Fruit Type
  • Capsule, 1-celled
Fruit Length at Maturity
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
  • 2.0 cm (.80 inch)
  • 2.5 cm (1.0 inch)
  • 3.0 cm (1.2 inches)
Fruit Width at Maturity
  • 8 mm (.32 inch)
  • 9 mm (.36 inch)
  • 1.0 cm (.40 inch)
Burs
  • Fruit or seed bur-like

Leaf Arrangement
  • Alternate
Leaf Type
  • Simple (including lobed leaves)
Stipules
  • Lacking
Tendrils
  • Tendrils absent
Venation
  • Pinnate
Petiole (leaf stem) Blade Ratio
  • Petiole absent (leaf sessile)
  • Petiole < 25% total length
Leaf Length (blade PLUS petiole)
  • 4 - 10 cm (1.60 - 4.0 inches)
Leaf Width
  • 1 - 2 cm (.40 - .80 inch)
Leaf Shape (simple leaves only)
  • Oblanceolate
Leaf or Leaflet Margin
  • Dentate
  • Serrate
Leaf or Leaflet Blade Base
  • Acuminate (attenuate)
Leaf or Leaflet Tip
  • Acute
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Scabrous (like sand paper)
  • Glochidiate (barbed)
Succulence
  • Not succulent

Milky Juice
  • Juice NOT milky (watery)
Woodiness
  • Herbaceous
Spines or Thorns
  • Spines or Thorns ABSENT
Aromatic (vegetative structures)
  • Not aromatic
Life Cycle
  • Biennial
  • Perennial
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
  • Arid
Chlorophyll
  • Present

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

Root or Vegetative Propagule
  • Tap Root

US State
  • Illinois
  • Kansas
  • Missouri
  • Texas
  • Arizona
  • Colorado
  • Montana
  • New Mexico
  • Oklahoma
  • South Dakota
  • Wyoming
  • Nebraska

  • Weeds of Nebraska and the Great Plains, 1994 (ISBN 0939870-00-4) See page: 353
  • Listed as a `Weed` by the Biota of North America Program, 2008 x
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