Weed Information: Monochoria vaginalis (monochoria)
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Monochoria vaginalis (monochoria)

Family: Pontederiaceae

Description

The leaf shape of this species varies with maturity and water depth thus making it difficult to identify the plants unless they are in flower. The flowers are blue to purple and occur in clusters which emerge from the sheath of the uppermost leaf. Each flower has six petals and six stamens with one stamen much longer than the other five.

Characteristics

Flower Color
  • Red (or pink)
  • Blue
  • Blue-purple
  • Purple
  • Multi-colored
Inflorescence Type (How the flowers are arranged on the plant)
  • Axillary racemes
  • Terminal raceme
Number of Petals
  • 3 petals
  • 6 petals
Petal Separation
  • United from 25% - 75% length
  • United > 75% of length
Petal Tip
  • Rounded
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.6 inch)
Flower Width (Head width in the Asteraceae)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
Number of Sepals
  • sepals lacking
  • 3 sepals
  • 6 sepals
Sepal Separation
  • United from 25% - 75% length
Sepal Tip
  • Rounded
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • 1 style
Number of Stamens
  • 6 stamens
Stamens Attached to the Petals
  • Stamens attached to the petals
Stamens Connate (united)
  • Filaments or anthers NOT united

Carpel Separation
  • Carpels united (or one)
Number of Carpels
  • 3 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Capsule, 3-celled
Fruit Length at Maturity
  • 8 mm (.32 inch)
  • 9 mm (.36 inch)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
Fruit Width at Maturity
  • 8 mm (.32 inch)
  • 9 mm (.36 inch)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
Burs
  • Fruit or seed NOT bur-like

Leaf Arrangement
  • All basal
Leaf Type
  • Simple (including lobed leaves)
Stipules
  • Lacking
Tendrils
  • Tendrils absent
Venation
  • Arcuate
  • Parallel
Petiole (leaf stem) Blade Ratio
  • Petiole > 75% total length
Leaf Length (blade PLUS petiole)
  • 1 - 2 dm (4.0 - 8.0 inches)
  • 2 - 4 dm (8.0 - 16.0 inches)
Leaf Width
  • 4 - 10 cm (1.6 - 4.0 inches)
Leaf Shape (simple leaves only)
  • Cordate (heart)
  • Elliptic
  • Lanceolate
  • Oval
  • Ovate
Succulence
  • Succulent
  • Not succulent
Leaf or Leaflet Margin
  • Entire
Leaf or Leaflet Blade Base
  • Acute (cuneate)
  • Cordate
  • Truncate
Leaf or Leaflet Tip
  • Acute
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Glabrous (NO hairs)

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)
  • Spreading ascending
  • Erect, spherical (bushy)
Plant Height at Maturity
  • 2 - 4 dm (8.0 - 16.0 inches)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Aquatic
Chlorophyll
  • Present

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

Root or Vegetative Propagule
  • Fibrous
  • Rhizomatous

US State
  • Hawaii
  • California

  • Aquatic and Riparian Plants of the West, 2003 (ISBN# 1-879906-59-7) See page: 342
  • California Growers Weed Identification Handbook, 1968 - 1998 University of California Publication # 4030-1, See page: 173
  • 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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