This order of eudicots contains more than 5,000 species, including various important weeds like giant hogweed. The members are herbs or woody plants characterized by the flowers being arranged in umbels, where the flower stalks originate from a common point on the stem. Typically, the flowers reach the same height, giving the structure an umbrella-like appearance. Other features are the compound or cleft leaves and the separate petals. The seeds contain a high concentration of petroselinic acid.
The group includes the following weed families: