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Weed Identification

sticky ragwort

Family

Asteraceae

Scientific Name

Senecio viscosus

Habit

Seedlings are hairless with oblong 3-11 mm long by 1-3 mm wide cotyledons. Mature plants have numerous branches reaching 75 cm and are covered with sticky hairs.

Leaves

Covered in short sticky hairs and alternate in arrangement leaves generally measure 3-12 cm long and are 1-5 cm wide. Stalkless and clasping, upper leaves are coarsely toothed to irregularly lobed. Meanwhile lower leaves are wavy-margined to deeply lobed.

Identifying Characteristics

Hollow stems, sticky hairs covering the entire plant with yellow flower heads composed of disc florets.

Flower Seed Head

7-15 mm across the flower heads are made up of 6-9 mm long yellow disk florets and a row of yellow-green floral bracts. Flower heads appear on the ends of branches.

Seed Fruit

The fruit a single-seeded achene contains a seed with 5-10 obvious veins ovate in shape, tan in color and 2-3 mm long. 3-4 mm long white bristles make up the pappus which aids is dispersal. A single plant can produce as many as 1,500 seeds

Where Found

Waste areas, railway grades, and roadsides are common homes for sticky groundsel.

Growth Habit

woody bush or tree

Thorns or Spines

not present

Approximate Flower Diameter

Varies: 
pencil
dime

Dominant Flower Color

Varies: 
yellow
red
orange

Flower Symmetry

radial symmetery

Leaf Hairs

Varies: 
no hairs
has hairs

Leaf Shape

spatulate

Leaf Arrangement

alternate

Leaf Margin

Varies: 
entire
lobed
serrated

Leaf Structure

Varies: 
pinnate
simple

Milky Sap

not present

Root Structure

taproot

Life Cycle

winter annual

Ochrea

not present

Plant Type

Herb