Weed Information: Delphinium geyeri (larkspur, Geyer)
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Delphinium geyeri (larkspur, Geyer)

Family: Ranunculaceae

Description

Up to 2 feet tall with coarse, hollow stems and finely divided leaves. On the plains and at low elevations in the mountains. A native wildflower included in weed references due to its toxicity to livestock rather than its weediness.

Characteristics

Flower Color
  • Blue
  • Blue-purple
  • Purple
  • White
  • Multi-colored
Inflorescence Type (How the flowers are arranged on the plant)
  • Axillary racemes
  • Terminal raceme
Number of Petals
  • 4 petals
  • 5 petals
Petal Separation
  • Completely free to base
Petal Tip
  • Bilobed
  • Erose
  • Pointed
  • Rounded
Flower Symmetry
  • Flowers strongly irregular
Flower Length (Head length in the Asteraceae)
  • 2.0 cm (.8 inch)
  • 2.5 cm (1.0 inch)
  • 3.0 cm (1.2 inches)
  • 3.5 cm (1.4 inches)
Flower Width (Head width in the Asteraceae)
  • 3 mm (.12 inch)
  • 4 mm (.16 inch)
  • 5 mm (.20 inch)
  • 6 mm (.24 inch)
  • 7 mm (.28 inch)
  • 8 mm (.32 inch)
Number of Sepals
  • 5 sepals
Sepal Separation
  • Completely free to base
Sepal Tip
  • Pointed
  • Rounded
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • 3 styles
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 separated
Number of Carpels
  • 3 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Follicle
Fruit Length at Maturity
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
  • 2.0 cm (.80 inch)
Fruit Width at Maturity
  • 2 mm (.08 inch)
  • 3 mm (.12 inch)
  • 4 mm (.16 inch)
  • 5 mm (.20 inch)
Burs
  • Fruit or seed NOT bur-like

Leaf Arrangement
  • Alternate
Leaf Type
  • Palmately dissected
  • Simple (including lobed leaves)
Stipules
  • Lacking
Tendrils
  • Tendrils absent
Venation
  • Palmate
Petiole (leaf stem) Blade Ratio
  • Petiole 25% - 75% total length
  • Petiole > 75% total length
Leaf Length (blade PLUS petiole)
  • 2 - 4 cm (.80 - 1.60 inches)
  • 4 - 10 cm (1.60 - 4.0 inches)
  • 1 - 2 dm (4.0 - 8.0 inches)
  • 2 - 4 dm (8.0 - 16.0 inches)
Leaf Width
  • 1 - 2 cm (.40 - .80 inch)
  • 2 - 4 cm (.80 - 1.6 inches)
  • 4 - 10 cm (1.6 - 4.0 inches)
Leaf Shape (simple leaves only)
  • Orbicular (round)
  • Palmately 3 lobed
  • Palmately 4 - 5 lobed
  • Palmately > 5 lobed
Leaf or Leaflet Margin
  • Lobed
  • Parted
Leaf or Leaflet Blade Base
  • Acute (cuneate)
  • Rounded
Leaf or Leaflet Tip
  • Acute
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Canescent
  • Strigose
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)
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)
  • 6 - 8 dm (2.0 - 2.6 feet)
  • 8 - 10 dm (2.6 - 3.3 feet)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Mesic
  • Arid
Chlorophyll
  • Present

Stem Cross Section
  • Hollow (flowering stem at maturity)
  • Round
Flowering Stem Leaves
  • Stem leaves greatly reduced
Main Stem Branches
  • Main stem unbranched
  • Main stem branched

Root or Vegetative Propagule
  • Fibrous
  • Tuberous

US State
  • Colorado
  • Utah
  • Wyoming
  • Nebraska

  • Common Weeds of the United States, 1971 (ISBN 0-486-20504-5) See page: 180
  • Weeds and Poisonous Plants of Wyoming and Utah 1987 (ISBN 0-941570-06-1) See page: 40
  • Weeds of Colorado, 1990 Cooperative Extension, Colorado State Univ. Bulletin 521A, See page: 73
  • Weeds of the West, 1992 (ISBN 0941570-13-4) See page: 524
  • Weeds of the West, 2000 (ISBN 0941570-13-4) See page: 518
  • 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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