Weed Information: Buglossoides arvensis (gromwell, corn)
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Buglossoides arvensis (gromwell, corn)

Family: Boraginaceae

Description

This annual species is a common weed of cultivated fields and produces a small, white, tubular flower. This is an excellent species to use to learn the fruit type referred to as `4 nutlets` which is typical of the borage, mint, and verbena families. Look down the stem from the flowers to find the cluster of 4 hard seeds surrounded by the 5 sepals. The 2000 edition of Weeds of the West has the cotyledon and true leaves confused in the description.

Characteristics

Flower Color
  • White
Inflorescence Type (How the flowers are arranged on the plant)
  • Scorpioid
  • Solitary, axillary
  • Terminal spike
Number of Petals
  • 5 petals
Petal Separation
  • United > 75% of length
Petal Tip
  • Rounded
Flower Symmetry
  • Flowers regular
Flower Length (Head length in the Asteraceae)
  • 5 mm (.20 inch)
  • 6 mm (.24 inch)
  • 7 mm (.28 inch)
  • 8 mm (.32 inch)
Flower Width (Head width in the Asteraceae)
  • 2 mm (.08 inch)
  • 3 mm (.12 inch)
  • 4 mm (.16 inch)
Number of Sepals
  • 5 sepals
Sepal Separation
  • United at base < 25% length
Sepal Tip
  • Pointed
Flower Sex
  • Bisexual (perfect)
Number of Styles
  • 1 style
Number of Stamens
  • 5 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
  • 4 carpels
Ovary Position
  • Superior (hypogynous)
Fruit Type
  • Nutlets, 4
Fruit Length at Maturity
  • 2 mm (.08 inch)
  • 3 mm (.12 inch)
Fruit Width at Maturity
  • 2 mm (.08 inch)
  • 3 mm (.12 inch)
  • 4 mm (.16 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
Leaf Length (blade PLUS petiole)
  • 1 - 2 cm (.40 - .80 inch)
  • 2 - 4 cm (.80 - 1.60 inches)
  • 4 - 10 cm (1.60 - 4.0 inches)
Leaf Width
  • 1 - 5 mm (.04 - .20 inch)
  • 5 - 10 mm (.20 - .40 inch)
  • 1 - 2 cm (.40 - .80 inch)
Leaf Shape (simple leaves only)
  • Lanceolate
  • Linear or filiform
Leaf or Leaflet Margin
  • Entire
Leaf or Leaflet Blade Base
  • Acute (cuneate)
  • Acuminate (attenuate)
  • Clasping
Leaf or Leaflet Tip
  • Acuminate (attenuate)
  • Acute
  • Rounded (obtuse)
Leaf or Leaflet Blade Surface
  • Scabrous (like sand paper)
  • 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
  • Annual
Growth Habit (while flowering)
  • Erect, columnar (narrow)
  • Erect, spherical (bushy)
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)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Mesic
Chlorophyll
  • Present

Stem Cross Section
  • Ridged
  • Round
  • Square
Flowering Stem Leaves
  • Stem uniformly leafy
Main Stem Branches
  • 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 Hampshire
  • New Jersey
  • New York
  • Ohio
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • Wisconsin
  • West Virginia
  • Indiana
  • Maryland
  • Rhode Island
  • Vermont
  • California
  • Colorado
  • Iowa
  • Idaho
  • Minnesota
  • Montana
  • North Dakota
  • Oklahoma
  • Oregon
  • South Dakota
  • Utah
  • Washington
  • Wyoming
  • Nebraska
Canadian Province or Territory
  • British Columbia
  • Nova Scotia
  • Ontario
  • Quebec
  • Manitoba
Other
  • District of Columbia
  • St. Pierre and Miquelon

  • Common Weeds of the United States, 1971 (ISBN 0-486-20504-5) See page: 304
  • Common Weed Seedlings of the United States and Canada, 1978 Coop Ext. Univ. of Georgia, Athens, See page: 8
  • Field Guide To The Common Weeds Of Kansas, 1983 (ISBN 0-7006-0233-X) See page: 92
  • Gilkey`s Weeds of the Pacific Northwest, 1980 (ISBN 0-88246-039-0) See page: 235
  • How to Know the Weeds, 1972, (ISBN# 0-697-04880-2) See page: 122
  • Manual of Ohio Weeds, 1931 Ohio Ag. Exp. Station Bull. # 475, See page: 83
  • Nebraska Weeds, 1979 Nebraska Dept. of Ag., Lincoln NE, See page: 148
  • Ontario Weeds, 1992 Agdex 640, Publication #505 See page: 171
  • Representative Missouri Weeds and Their Control, 1941 Univ. of Missouri Ag. Exp Station Bulletin #433, See page: 147
  • S.W.S.S. Weed ID Guide, 1993 Section Number and Five letter code: 11 LITAR
  • Weed Seeds of the Great Plains, 1993 University of Kansas# 92-125-B ISBN# 0-7006-0651-3 See index #: 163
  • Weeds, 1955 (1980) Walter Conrad Muenscher, ISBN# 0-8014-1266-8 See page: 361, 363
  • Weeds, A Golden Guide, 1972 ISBN#0-307-24353-2 See page: 96
  • Weeds of Arkansas 1981 (MP 169-5M-3-81) See page: 3
  • Weeds of Eastern Washington and Adjacent Areas, 1972 (LOC 72-83635) See page: 228
  • Weeds of Kentucky and Adjacent States, 1991 (ISBN 0-8131-1743-7) See page: 22
  • Weeds of Nebraska and the Great Plains, 1994 (ISBN 0939870-00-4) See page: 188
  • Weeds of the Midwestern United States & Central Canada, University of Georgia 2010, ISBN#0-8203-3506-1 See page: 136
  • Weeds of the Northeast, 1956, Univ. of Delaware Field Manual #1 See species #: 45
  • Weeds of the Northern United States and Canada, 1964 Montgomery See page: 129
  • Weeds of the South, University of Georgia 2009, ISBN#0-8203-3046-9 See page: 118
  • Weeds of the United States and Their Control, Lorenzi 1987, ISBN# 0-442-25884-4 See page: 247
  • Weeds of the West, 1992 (ISBN 0941570-13-4) See page: 206
  • Weeds of the West, 2000 (ISBN 0941570-13-4) See page: 206
  • Weeds of Utah, 1971 UAES Special Report 21, See page: 72
  • 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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