Weed Information: Brassica nigra (mustard, black)
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Brassica nigra (mustard, black)

Family: Brassicaceae

Description

Black mustard is one of the largest species in this genus, often reaching heights of 6 feet. The fruits are erect and strongly appressed to the flowering stem. The lower leaves have sparse, pustulate (pimple-like) based hairs on the upper leaf surface. This is the species used to prepare the extremely `hot` mustard one encounters in Chinese restaurants.

Characteristics

Flower Color
  • Yellow
Inflorescence Type (How the flowers are arranged on the plant)
  • Axillary racemes
  • Terminal raceme
Number of Petals
  • 4 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)
  • 8 mm (.32 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)
  • 2.0 cm (.80 inch)
Number of Sepals
  • 4 sepals
Sepal Separation
  • Completely free to base
Sepal Tip
  • Pointed
  • Rounded
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • 1 style
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 united (or one)
Number of Carpels
  • 2 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Capsule, 2-celled
Fruit Length at Maturity
  • 1.0 cm (.40 inch)
  • 1.5 cm (.60 inch)
  • 2.0 cm (.80 inch)
  • 2.5 cm (1.0 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
  • Alternate
Leaf Type
  • Simple (including lobed leaves)
Stipules
  • Lacking
Tendrils
  • Tendrils absent
Venation
  • Pinnate
Petiole (leaf stem) Blade Ratio
  • Petiole absent (leaf sessile)
  • Petiole < 25% total length
  • Petiole 25% - 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)
  • Elliptic
  • Lyrate
  • Ovate
  • Pinnately lobed
Leaf or Leaflet Margin
  • Dentate
  • Lobed
  • Parted
  • Serrate
Leaf or Leaflet Blade Base
  • Auriculate
  • Clasping
  • Oblique
  • Rounded
  • Truncate
Leaf or Leaflet Tip
  • Acute
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Glabrous (NO hairs)
  • Hirsute
  • Hispid or setose
  • Sparsely hairy
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
  • Annual
Growth Habit (while flowering)
  • Erect, columnar (narrow)
Plant Height at Maturity
  • 4 - 6 dm (1.3 - 2.0 feet)
  • 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)
  • 1.5 - 2.0 meters (5.0 - 6.6 feet)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Mesic
Chlorophyll
  • Present

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

Root or Vegetative Propagule
  • Tap Root

US State
  • Alabama
  • Connecticut
  • Delaware
  • Florida
  • Illinois
  • Kansas
  • Kentucky
  • Louisiana
  • Massachusetts
  • Maine
  • Michigan
  • Missouri
  • Mississippi
  • North Carolina
  • New Hampshire
  • New Jersey
  • New York
  • Ohio
  • Pennsylvania
  • Tennessee
  • Texas
  • Virginia
  • Wisconsin
  • West Virginia
  • Hawaii
  • Indiana
  • Maryland
  • Rhode Island
  • Vermont
  • Arizona
  • California
  • Colorado
  • Iowa
  • Idaho
  • Minnesota
  • Montana
  • North Dakota
  • New Mexico
  • Nevada
  • Oklahoma
  • Oregon
  • South Dakota
  • Utah
  • Washington
  • Nebraska
Canadian Province or Territory
  • British Columbia
  • New Brunswick
  • Nova Scotia
  • Ontario
  • Prince Edward Island
  • Quebec
  • Newfoundland
  • Saskatchewan
Other
  • District of Columbia
  • St. Pierre and Miquelon

  • An Illustrated Guide To Arizona Weeds, 1972 (ISBN 0-8165-0288-9) 338 pages. See page: 140
  • California Growers Weed Identification Handbook, 1968 - 1998 University of California Publication # 4030-1, See page: 8
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  • Northwest Weeds, 1990 (ISBN 0-87842-249-8) See page: 41
  • Ontario Weeds, 1992 Agdex 640, Publication #505 See page: 90
  • Representative Missouri Weeds and Their Control, 1941 Univ. of Missouri Ag. Exp Station Bulletin #433, See page: 101
  • Some Weedy Plants of North Carolina, 1955 North Carolina Ag. Ext. Circular # 390, See page: 28
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  • Weeds of California, 1970, State of California Publications and Documents. See page: 213, 214
  • Weeds of California and other Western States, 2007 (ISBN 13: 978-1-879906-69-3) See Page: 460
  • Weeds of Canada, 1970 Canada Dept. of Ag., Pub. # 948, See page: 93
  • Weeds of Colorado, 1990 Cooperative Extension, Colorado State Univ. Bulletin 521A, See page: 80
  • Weeds of Eastern Washington and Adjacent Areas, 1972 (LOC 72-83635) See page: 140
  • Weeds of Nebraska and the Great Plains, 1994 (ISBN 0939870-00-4) See page: 195
  • Weeds of the Midwestern United States & Central Canada, University of Georgia 2010, ISBN#0-8203-3506-1 See page: 144
  • Weeds of the North Central States, 1981 Univ. of Illinois, Urbana - Champaign Bulletin # 772, See page: 88
  • Weeds of the Northeast, 1956, Univ. of Delaware Field Manual #1 See species #: 269
  • Weeds of the Northeast, 1997 Cornell University ISBN# 0-8014-8334-4 See page: 170
  • Weeds of the Northern United States and Canada, 1964 Montgomery See page: 69
  • Weeds of the South, University of Georgia 2009, ISBN#0-8203-3046-9 See page: 121
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  • Weeds of the West, 1992 (ISBN 0941570-13-4) See page: 214
  • Weeds of the West, 2000 (ISBN 0941570-13-4) See page: 212
  • Weeds of Utah, 1971 UAES Special Report 21, See page: 41
  • 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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