Weed Information: Citrullus lanatus (citronmelon)
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Citrullus lanatus (citronmelon)

Family: Cucurbitaceae

Description

Closely related to the watermelon but with a small fruit with a thick rind. The specific epithet `lanatus` translates `wooly` and the long, soft, wooly hairs of the stem are very evident.

Characteristics

Flower Color
  • Yellow
Inflorescence Type (How the flowers are arranged on the plant)
  • Solitary, axillary
Number of Petals
  • 5 petals
Petal Separation
  • United at base only (<25% length)
Petal Tip
  • Pointed
  • Rounded
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.6 inch)
  • 2.0 cm (.8 inch)
  • 2.5 cm (1.0 inch)
  • 3.0 cm (1.2 inches)
Flower Width (Head width in the Asteraceae)
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
  • 2.0 cm (.80 inch)
  • 2.5 cm (1.0 inch)
  • 3.0 cm (1.2 inches)
  • 3.5 cm (1.4 inches)
  • 4.0 cm (1.6 inches)
Number of Sepals
  • 5 sepals
Sepal Separation
  • United from 25% - 75% length
  • United > 75% of length
Sepal Tip
  • Pointed
Flower Sex
  • Unisexual (monoecious or dioecious)
Number of Styles
  • Styles lacking (male flowers only)
  • 1 style
Number of Stamens
  • stamens lacking (female flowers only)
  • 3 stamens
  • 5 stamens
Stamens Attached to the Petals
  • Stamens NOT attached to the petals
Stamens Connate (united)
  • Filaments united, monodelphous

Carpel Separation
  • Carpels united (or one)
Number of Carpels
  • 0 (male flowers only or plants producing spores)
  • 3 carpels
Ovary Position
  • Inferior (epigynous)
Fruit Type
  • Berry, green
  • Melon or Gourd
Fruit Length at Maturity
  • 5.0 cm (2.0 inches)
  • 6.0 cm (2.4 inches)
  • 7.0 cm (2.8 inches)
  • 8.0 cm (3.2 inches)
  • 9.0 cm (3.6 inches)
  • 1.0 dm (4.0 inches)
  • > 1.5 dm (> 6.0 inches)
  • 1.5 dm (6.0 inches)
Fruit Width at Maturity
  • 4.0 cm (1.8 inches)
  • more than 4.0 cm (> 1.8 inches)
Burs
  • Fruit or seed NOT bur-like

Leaf Arrangement
  • Alternate
Leaf Type
  • Pinnately dissected
  • Simple (including lobed leaves)
Stipules
  • Lacking
Tendrils
  • Tendrils present
Venation
  • Pinnate
Petiole (leaf stem) Blade Ratio
  • Petiole < 25% total length
  • Petiole 25% - 75% total length
Leaf Length (blade PLUS petiole)
  • 4 - 10 cm (1.60 - 4.0 inches)
  • 1 - 2 dm (4.0 - 8.0 inches)
Leaf Width
  • 4 - 10 cm (1.6 - 4.0 inches)
Leaf Shape (simple leaves only)
  • Pinnately lobed
Leaf or Leaflet Margin
  • Lobed
  • Parted
Leaf or Leaflet Blade Base
  • Cordate
  • Rounded
Leaf or Leaflet Tip
  • Acute
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Sericeous or villous (silky)
  • Villous or sericious (silky)
Succulence
  • Not succulent

Milky Juice
  • Juice NOT milky (watery)
Woodiness
  • Herbaceous
Spines or Thorns
  • Spines or Thorns ABSENT
Aromatic (vegetative structures)
  • Not aromatic
  • Aromatic
Life Cycle
  • Annual
Growth Habit (while flowering)
  • Prostrate
  • Climbing vine
Plant Height at Maturity
  • 5 - 10 cm (2.0 - 4.0 inches)
  • 1 - 2 dm (4.0 - 8.0 inches)
  • 2 - 4 dm (8.0 - 16.0 inches)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Mesic
  • Arid
Chlorophyll
  • Present

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

Root or Vegetative Propagule
  • Tap Root

US State
  • Alabama
  • Arkansas
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Kansas
  • Kentucky
  • Louisiana
  • Massachusetts
  • Maine
  • Michigan
  • Missouri
  • Mississippi
  • North Carolina
  • New Jersey
  • New York
  • Ohio
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • Wisconsin
  • West Virginia
  • Indiana
  • Maryland
  • Rhode Island
  • Vermont
  • Arizona
  • California
  • New Mexico
  • Nevada
  • Oklahoma
  • Utah
Other
  • Puerto Rico
  • Virgin Islands
Canadian Province or Territory
  • New Brunswick
  • Ontario
  • Quebec

  • California Growers Weed Identification Handbook, 1968 - 1998 University of California Publication # 4030-1, See page: 131
  • S.W.S.S. Weed ID Guide, 1993 Section Number and Five letter code: 10 CITLC
  • Weeds of California, 1970, State of California Publications and Documents. See page: 309
  • Weeds of California and other Western States, 2007 (ISBN 13: 978-1-879906-69-3) See Page: 654
  • Weeds of the South, University of Georgia 2009, ISBN#0-8203-3046-9 See page: 176
  • Weeds of the Southern United States, 1975, North Carolina Ag. Extension Circular #599 See page: 19
  • 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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