Weed Information: Alisma triviale (waterplantain, common)
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Alisma triviale (waterplantain, common)

Family: Alismataceae

Description

A common, native, aquatic plant. The flowers are very similar to those of the arrowheads (3 white petals) but arranged in a broad panicle and the leaves do not have prominent basal lobes.

Characteristics

Flower Color
  • White
Inflorescence Type (How the flowers are arranged on the plant)
  • Panicle
Number of Petals
  • 3 petals
Petal Separation
  • Completely free to base
Petal Tip
  • Rounded
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • 4 mm (.16 inch)
  • 5 mm (.20 inch)
  • 6 mm (.24 inch)
  • 7 mm (.28 inch)
Flower Width (Head width in the Asteraceae)
  • 9 mm (.36 inch)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
  • 2.0 cm (.80 inch)
Number of Sepals
  • 3 sepals
Sepal Separation
  • Completely free to base
Sepal Tip
  • Pointed
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • More than 10 styles
Number of Stamens
  • 6 stamens
Stamens Attached to the Petals
  • Stamens NOT attached to the petals
Stamens Connate (united)
  • Filaments or anthers NOT united

Carpel Separation
  • Carpels separated
Number of Carpels
  • >10 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Achene
Fruit Length at Maturity
  • 2 mm (.08 inch)
  • 3 mm (.12 inch)
Fruit Width at Maturity
  • 1 mm (.04 inch) or less
  • 2 mm (.08 inch)
Burs
  • Fruit or seed NOT bur-like

Leaf Arrangement
  • All basal
Leaf Type
  • Simple (including lobed leaves)
Stipules
  • Lacking
Tendrils
  • Tendrils absent
Venation
  • Palmate
  • 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
  • 2 - 4 cm (.80 - 1.6 inches)
  • 4 - 10 cm (1.6 - 4.0 inches)
Leaf Shape (simple leaves only)
  • Elliptic
  • Oblong
  • Ovate
Leaf or Leaflet Margin
  • Entire
Leaf or Leaflet Blade Base
  • Acute (cuneate)
  • Rounded
  • Truncate
Leaf or Leaflet Tip
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Glabrous (NO hairs)
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
  • 6 - 8 dm (2.0 - 2.6 feet)
  • 8 - 10 dm (2.6 - 3.3 feet)
  • 1 - 1.5 meters (3.3 - 5.0 feet)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Aquatic
Chlorophyll
  • Present

Stem Cross Section
  • Hollow (flowering stem at maturity)
  • Round
Flowering Stem Leaves
  • Stem leafless
Main Stem Branches
  • Main stem unbranched

Root or Vegetative Propagule
  • Bulb or Corm
  • Fibrous

US State
  • Arkansas
  • Connecticut
  • Illinois
  • Kansas
  • Kentucky
  • Massachusetts
  • Maine
  • Michigan
  • Missouri
  • New Hampshire
  • New Jersey
  • New York
  • Ohio
  • Pennsylvania
  • Wisconsin
  • West Virginia
  • Indiana
  • Maryland
  • Rhode Island
  • Vermont
  • Alaska
  • Arizona
  • California
  • Colorado
  • Iowa
  • Idaho
  • Minnesota
  • Montana
  • North Dakota
  • New Mexico
  • Nevada
  • Oklahoma
  • Oregon
  • South Dakota
  • Utah
  • Washington
  • Wyoming
  • Nebraska
Canadian Province or Territory
  • British Columbia
  • New Brunswick
  • Nova Scotia
  • Ontario
  • Prince Edward Island
  • Quebec
  • Alberta
  • Manitoba
  • Newfoundland
  • Saskatchewan
  • Yukon
  • Northwest Territory

  • Aquatic and Riparian Plants of the West, 2003 (ISBN# 1-879906-59-7) See page: 137
  • California Growers Weed Identification Handbook, 1968 - 1998 University of California Publication # 4030-1, See page: 171
  • Weeds of California, 1970, State of California Publications and Documents. See page: 41, 42
  • 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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