FAO - Parthenium hysterophorus L.
Common names: Whitetop, Whitehead, Barley flower, Congress Grass, Amargosa, Escoba Amarga
An erect annual herb with alternate, deeply-dissected leaves, growing up to 2 m tall with much branched inflorescences bearing white flower heads and numerous obovoid, smooth and black achenes.
Parthenium is a native of tropical America and was introduced into Africa, Asia and Oceania in cereal and grass seed shipments from U.S.A. during the 1950s.
Parthenium is wide-spread in grassland, fruit tree orchards and arable land in neutral and acid soils.