Weed Information: Ricinus communis (castorbean)
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Ricinus communis (castorbean)

Family: Euphorbiaceae

Description

Castorbean was introduced as a medicinal plant (castor oil) but is very poisonous if taken incorrectly due to the presence of ricin, one of the most toxic plant chemicals known! Its large, palmately divided leaves are very distinctive in shape and may be green or dark purple. In colder areas this species can act as an annual but in warmer climates it becomes a tree; very few species are adapted in this manner.

Characteristics

Flower Color
  • Green
Inflorescence Type (How the flowers are arranged on the plant)
  • Axillary racemes
  • Panicle
Number of Petals
  • 0 (no petals)
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • 7 mm (.28 inch)
  • 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)
  • 7 mm (.28 inch)
  • 8 mm (.32 inch)
  • 9 mm (.36 inch)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
Number of Sepals
  • 3 sepals
  • 4 sepals
  • 5 sepals
Sepal Separation
  • United at base < 25% length
Sepal Tip
  • Pointed
Flower Sex
  • Unisexual (monoecious or dioecious)
Number of Styles
  • Styles lacking (male flowers only)
  • 3 styles
Number of Stamens
  • stamens lacking (female flowers only)
  • 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 united (or one)
Number of Carpels
  • 0 (male flowers only or plants producing spores)
  • 3 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Capsule, 3-celled
Fruit Length at Maturity
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
  • 2.0 cm (.80 inch)
Fruit Width at Maturity
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
  • 2.0 cm (.80 inch)
Burs
  • Fruit or seed NOT bur-like
  • Fruit or seed bur-like

Leaf Arrangement
  • Alternate
Leaf Type
  • 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)
  • 1 - 2 dm (4.0 - 8.0 inches)
  • 2 - 4 dm (8.0 - 16.0 inches)
  • 4 - 6 dm (1.3 - 2.0 feet)
Leaf Width
  • 1 - 2 dm (4.0 - 8.0 inches)
  • 2 - 4 dm (8.0 - 16.0 inches)
Leaf Shape (simple leaves only)
  • Orbicular (round)
  • Palmately > 5 lobed
Leaf or Leaflet Margin
  • Dentate
  • Lobed
  • Parted
  • Serrate
Succulence
  • Succulent
  • Not succulent
Leaf or Leaflet Blade Base
  • Truncate
Leaf or Leaflet Tip
  • Acuminate (attenuate)
  • Acute
Leaf or Leaflet Blade Surface
  • Glabrous (NO hairs)

Milky Juice
  • Juice NOT milky (watery)
Woodiness
  • Herbaceous
  • Semi-woody
  • Woody
Spines or Thorns
  • Spines or Thorns ABSENT
  • Spines on flowers or fruits only
Aromatic (vegetative structures)
  • Not aromatic
  • Aromatic
Life Cycle
  • Annual
  • Perennial
Growth Habit (while flowering)
  • Erect, columnar (narrow)
  • Erect, spherical (bushy)
Plant Height at Maturity
  • 1 - 1.5 meters (3.3 - 5.0 feet)
  • 1.5 - 2.0 meters (5.0 - 6.6 feet)
  • 2 - 2.5 meters (6.6 - 8.3 feet)
  • 2.5 - 5 meters (8.3 - 16.6 feet)
  • more than 5.0 meters (16.6 33 feet)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Mesic
Chlorophyll
  • Present

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

Root or Vegetative Propagule
  • Tap Root

US State
  • Alabama
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Kansas
  • Louisiana
  • Massachusetts
  • Michigan
  • Missouri
  • Mississippi
  • North Carolina
  • New Hampshire
  • New Jersey
  • New York
  • Ohio
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • Hawaii
  • Indiana
  • Maryland
  • Arizona
  • California
  • Utah
Other
  • Puerto Rico
  • Virgin Islands
  • District of Columbia

  • More Turfgrass and Related Weeds: Beyond the Color Atlas, 2011 Clemson University Publishing ISBN# 978-0-9798777-5-9 See Page: 235
  • Weeds of California, 1970, State of California Publications and Documents. See page: 287
  • Weeds of California and other Western States, 2007 (ISBN 13: 978-1-879906-69-3) See Page: 728
  • Weeds of the West, 1992 (ISBN 0941570-13-4) See page: 318
  • Weeds of the West, 2000 (ISBN 0941570-13-4) See page: 316
  • 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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