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Weed Identification

American burnweed

Family

Asteraceae

Scientific Name

Erechtites hieracifolia

Other Common Names:

pilewort
fire weed

Synonyms (former Scientific Names):

Erechtites hieraciifolius
Erechtites hieracifolia

Habit

This weed is an erect summer annual that ranges in height from 1 to 9 feet tall.

Leaves

Alternate, elliptic to lanceolate in outline, approximately 2 to 8 inches long, 1/2 to 2 1/2 inches wide. Leaves have a sharp-pointed apex (acute) and margins that are irregularly toothed. Most leaves will not be lobed but it is possible.

Identifying Characteristics

An erect summer annual with alternate, lanceolate leaves that have toothed margins. Erect plants with alternate, lanceolate leaves that have toothed margins. When mature, the feathery white seedheads are also key features of these plants.

Flower Seed Head

Flowers occur in panicles at the ends of stems. Individual flower heads are 3 to 10 mm wide, and cream to pinkish in color.

Seed Fruit

A brown nutlet that contains many white pappus that disperse the seed.

Where Found

Fireweed is primarily a weed of pastures, abandoned fields, and some agronomic crops.

Growth Habit

upright and nonwoody

Thorns or Spines

not present

Approximate Flower Diameter

Varies: 
pencil
dime

Dominant Flower Color

Varies: 
white
pink

Flower Symmetry

Varies: 
radial symmetery
bilateral symmetry
not symmetrical

Leaf Hairs

Varies: 
has hairs
no hairs

Leaf Arrangement

alternate

Leaf Margin

Varies: 
lobed
serrated

Leaf Structure

simple

Leaf Stalk

Varies: 
none
shorter than leaf

Stem Hairs

Varies: 
has hairs
no hairs

Stem Cross Section

round or oval

Milky Sap

not present

Root Structure

Varies: 
fibrous
taproot

Life Cycle

summer annual

Ochrea

not present

Plant Type

Herb