Weed Information: Helenium autumnale (sneezeweed, common)
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Helenium autumnale (sneezeweed, common)

Family: Asteraceae

Description

Both ray and disk flowers yellow; the center raised and rounded; the ray flowers with toothed tips. The leaf bases extending along the main stem as narrow wings. This species is commonly found along the margins of streams, often within the zone of fluctuation. It is reportedly toxic to all classes of livestock. For further information on this and other poisonous plants, see Poisonous Plants of the United States and Canada by Kingsbury.

Characteristics

Flower Color
  • Yellow
Inflorescence Type (How the flowers are arranged on the plant)
  • Corymb
  • Head
  • Solitary, terminal
Number of Petals
  • 5 petals
  • 10 petals
  • more than 10 petals
Petal Separation
  • Completely free to base
  • United > 75% of length
Petal Tip
  • Toothed
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)
  • 2.0 cm (.80 inch)
  • 2.5 cm (1.0 inch)
  • 3.0 cm (1.2 inches)
Number of Sepals
  • sepals lacking
  • more than 10 sepals
Sepal Separation
  • Completely free to base
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)
  • Anthers united, syngynoecious

Carpel Separation
  • Carpels united (or one)
Number of Carpels
  • 1 carpel
Ovary Position
  • Inferior (epigynous)
Fruit Type
  • Achene
Fruit Length at Maturity
  • 1 mm (.04 inch) or less
  • 2 mm (.08 inch)
Fruit Width at Maturity
  • 1 mm (.04 inch) or less
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)
  • 4 - 10 cm (1.60 - 4.0 inches)
  • 1 - 2 dm (4.0 - 8.0 inches)
Leaf Width
  • 1 - 2 cm (.40 - .80 inch)
  • 2 - 4 cm (.80 - 1.6 inches)
Leaf Shape (simple leaves only)
  • Elliptic
  • Lanceolate
  • Linear or filiform
  • Ovate
Leaf or Leaflet Margin
  • Serrate
Leaf or Leaflet Blade Base
  • Acute (cuneate)
  • Acuminate (attenuate)
  • Clasping
Leaf or Leaflet Tip
  • Acuminate (attenuate)
  • Acute
Leaf or Leaflet Blade Surface
  • Glabrous (NO hairs)
  • Pubescent
  • 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
  • Perennial
Growth Habit (while flowering)
  • Erect, columnar (narrow)
Plant Height at Maturity
  • 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)
  • 1 - 1.5 meters (3.3 - 5.0 feet)
Wind Dissemination
  • Not wind disseminated
Moisture Regime
  • Semi-aquatic
  • Seasonally saturated
  • Mesic
Chlorophyll
  • Present

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

Root or Vegetative Propagule
  • Fibrous
  • Rhizomatous

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
  • Colorado
  • Iowa
  • Idaho
  • Minnesota
  • Montana
  • North Dakota
  • New Mexico
  • Nevada
  • Oklahoma
  • Oregon
  • South Dakota
  • Utah
  • Washington
  • Wyoming
  • Nebraska
Canadian Province or Territory
  • British Columbia
  • Ontario
  • Quebec
  • Alberta
  • Manitoba
  • Saskatchewan
  • Northwest Territory
Other
  • District of Columbia

  • Common Weeds of the Canadian Prairies, 1963 (Cat# A53-1136-1) See page: 41
  • Field Guide To The Common Weeds Of Kansas, 1983 (ISBN 0-7006-0233-X) See page: 118
  • How to Know the Weeds, 1972, (ISBN# 0-697-04880-2) See page: 181
  • Ontario Weeds, 1992 Agdex 640, Publication #505 See page: 211
  • South Dakota Weeds, 1967 South Dakota State University, See page: 193
  • Weed Seeds of the Great Plains, 1993 University of Kansas# 92-125-B ISBN# 0-7006-0651-3 See index #: 223
  • Weeds, 1955 (1980) Walter Conrad Muenscher, ISBN# 0-8014-1266-8 See page: 469
  • Weeds of Nebraska and the Great Plains, 1994 (ISBN 0939870-00-4) See page: 142
  • Weeds of the Midwestern United States & Central Canada, University of Georgia 2010, ISBN#0-8203-3506-1 See page: 101
  • Weeds of the North Central States, 1981 Univ. of Illinois, Urbana - Champaign Bulletin # 772, See page: 215
  • Weeds of the South, University of Georgia 2009, ISBN#0-8203-3046-9 See page: 83
  • Weeds of the United States and Their Control, Lorenzi 1987, ISBN# 0-442-25884-4 See page: 316
  • Weeds of Utah, 1971 UAES Special Report 21, See page: 99
  • 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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