Weed Information: Bacopa eisenii (waterhyssop, Eisen)
Back to Plant List

Bacopa eisenii (waterhyssop, Eisen)

Family: Scrophulariaceae

Description

A trailing or creeping aquatic annual with hollow stems often rooting at the nodes. The leaves are round and opposite.

Characteristics

Flower Color
  • Yellow
  • White
  • Multi-colored
Inflorescence Type (How the flowers are arranged on the plant)
  • Axillary cluster
  • Solitary, axillary
Number of Petals
  • 5 petals
Petal Separation
  • United at base only (<25% length)
  • United from 25% - 75% length
Petal Tip
  • Rounded
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • 8 mm (.32 inch)
  • 9 mm (.36 inch)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.6 inch)
Flower Width (Head width in the Asteraceae)
  • 8 mm (.32 inch)
  • 9 mm (.36 inch)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
Number of Sepals
  • 5 sepals
Sepal Separation
  • United from 25% - 75% length
Sepal Tip
  • Pointed
  • Rounded
  • Toothed
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • 1 style
Number of Stamens
  • 4 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
  • 2 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Capsule, 2-celled
Fruit Length at Maturity
  • 3 mm (.12 inch)
  • 4 mm (.16 inch)
  • 5 mm (.20 inch)
  • 6 mm (.24 inch)
Fruit Width at Maturity
  • 1 mm (.04 inch) or less
  • 2 mm (.08 inch)
  • 3 mm (.12 inch)
Burs
  • Fruit or seed NOT bur-like

Leaf Arrangement
  • Opposite
Leaf Type
  • Simple (including lobed leaves)
Stipules
  • Lacking
Tendrils
  • Tendrils absent
Venation
  • Palmate
Petiole (leaf stem) Blade Ratio
  • Petiole absent (leaf sessile)
Leaf Length (blade PLUS petiole)
  • 1 - 2 cm (.40 - .80 inch)
Leaf Width
  • 1 - 2 cm (.40 - .80 inch)
Leaf Shape (simple leaves only)
  • Orbicular (round)
Succulence
  • Succulent
  • Not succulent
Leaf or Leaflet Margin
  • Entire
Leaf or Leaflet Blade Base
  • Acute (cuneate)
Leaf or Leaflet Tip
  • 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
  • Annual
Growth Habit (while flowering)
  • Prostrate
  • Spreading ascending
  • Floating
Plant Height at Maturity
  • 1 - 5 cm (.40 - 2.0 inches)
  • 5 - 10 cm (2.0 - 4.0 inches)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Aquatic
Chlorophyll
  • Present

Stem Cross Section
  • Hollow (flowering stem at maturity)
  • Round
  • Square
Flowering Stem Leaves
  • Stem uniformly leafy
Main Stem Branches
  • Main stem branched

Root or Vegetative Propagule
  • Fibrous
  • Rooting at the nodes

US State
  • California
  • Nevada

  • Aquatic and Riparian Plants of the West, 2003 (ISBN# 1-879906-59-7) See page: 359
  • California Growers Weed Identification Handbook, 1968 - 1998 University of California Publication # 4030-1, See page: 175
  • Listed as a `Weed` by the Biota of North America Program, 2008 X
  • Listed in the WSSA Composite List of Weeds X
Back to Plant List