Weed Information: Oenothera speciosa (eveningprimrose, showy)
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Oenothera speciosa (eveningprimrose, showy)

Family: Onagraceae

Description

A native wildflower of the Great Plains with large, white, 4-petalled flowers that turn pinkish-purple as they fade. The fruit is a 4-chambered capsule from an inferior ovary.

Characteristics

Flower Color
  • Red (or pink)
  • Red-purple
  • White
Inflorescence Type (How the flowers are arranged on the plant)
  • Solitary, axillary
  • Terminal raceme
Number of Petals
  • 4 petals
Petal Separation
  • Completely free to base
Petal Tip
  • Bilobed
  • Rounded
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)
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
  • 4 sepals
Sepal Separation
  • Completely free to base
Sepal Tip
  • Pointed
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • 1 style
Number of Stamens
  • 8 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
  • 4 carpels
Ovary Position
  • Inferior (epigynous)
Fruit Type
  • Capsule, > 3-celled
Fruit Length at Maturity
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
Fruit Width at Maturity
  • 3 mm (.12 inch)
  • 4 mm (.16 inch)
  • 5 mm (.20 inch)
  • 6 mm (.24 inch)
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 absent (leaf sessile)
  • Petiole < 25% 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
  • Lanceolate
  • Oblanceolate
  • Oblong
  • Ovate
  • Pinnately lobed
Leaf or Leaflet Margin
  • Entire
  • Lobed
  • Undulate (sinuate, repand)
Leaf or Leaflet Blade Base
  • Acute (cuneate)
  • Rounded
Leaf or Leaflet Tip
  • Acute
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Sericeous or villous (silky)
  • Strigose
  • Villous or sericious (silky)
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
  • Perennial
Growth Habit (while flowering)
  • Erect, columnar (narrow)
  • Erect, spherical (bushy)
Plant Height at Maturity
  • 1 - 2 dm (4.0 - 8.0 inches)
  • 2 - 4 dm (8.0 - 16.0 inches)
  • 4 - 6 dm (1.3 - 2.0 feet)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Mesic
  • Arid
Chlorophyll
  • Present

Stem Cross Section
  • Round
Flowering Stem Leaves
  • Stem leaves greatly reduced
Main Stem Branches
  • Main stem unbranched
  • Main stem branched

Root or Vegetative Propagule
  • Fibrous
  • Rhizomatous
  • Tap Root

US State
  • Alabama
  • Arkansas
  • Connecticut
  • Florida
  • Georgia
  • Illinois
  • Kansas
  • Kentucky
  • Louisiana
  • Missouri
  • Mississippi
  • North Carolina
  • Ohio
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • West Virginia
  • Indiana
  • Arizona
  • California
  • Iowa
  • New Mexico
  • Oklahoma
  • Utah
  • Nebraska

  • Garden Weeds of Southern California, 1981, See page: 76
  • How to Know the Weeds, 1972, (ISBN# 0-697-04880-2) See page: 111
  • Weeds of Arkansas 1981 (MP 169-5M-3-81) See page: 48
  • Weeds of California and other Western States, 2007 (ISBN 13: 978-1-879906-69-3) See Page: 975
  • Weeds of Southern Turfgrasses, 1992 Univ. of Florida, Gainesville Publication # SP-79, See page: 156
  • Weeds of the South, University of Georgia 2009, ISBN#0-8203-3046-9 See page: 244
  • 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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