Parthenium hysterophorus
false ragweed, santa maria feverfew, ragweed parthenium, whitetop weed, cicutilla
Family
Asteraceae
Leaf Arrangement
alternate
Leaf Attachment
petiolate
Leaf Margin
entire, bi-pinnatifid, pinnatifid, toothed
Leaf Type
bipinnate, compound, pinnate
Growth Form
forb
Flower Color
white
Flower Month
June - November
Height (meters)
0.3 - 1.0
Milky Sap
No
Armed/Unarmed
Unarmed
Origin
introduced
Lifespan
annual
Growing Season
Warm season
Prairie Coefficient of Conservatism
-1
Field Characters
Lowermost leaves forming a rosette, pinnate to bipinnately lobed, petiolate, up to 200 mm long and 100 mm wide overall; upper leaves becoming shallow lobed to subentire and sessile or nearly so.
Natural History
A widely occurring and abundant weed in clay soils. It can be found in flower throughout the year in south Louisiana.
Habitat
Open waste ground.