Scientific Name: Ambrosia bidentata

Common Name: lanceleaf ragweed

Other Common Names: southern ragweed

Habit: Branching annual

Leaves: Leaves are opposite below and alternate above; have a lanceolate shape with no lobes and no leaf stalk. Often, the leaves will have one pair of large teeth on the lower half of the leaf. Leaves are densely hairy mostly on the underside. The upper side of the leaf may be hairless.

Identifying Characteristics: This is an annual weed that is highly branching and can grow up to 3 ft tall. Both the stem and leaves are densely covered in long, straight (not woolly) hairs. Often, the leaves will have one pair of large teeth on the half of the leaf nearest to the stem; otherwise, the leaves may be finely toothed or may not have any teeth at all.

Flower Seed Head: Flowers are non-showy. The inflorescence is a tall, ascending spike.

Seed Fruit: Hairy bur. Fruit has several short stiff spines and is beaked at one end.

Where Found: Commonly found in prairies and waste areas

  • Life cycle: summer annual

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Not Present

  • Plant family: Asteraceae

  • Leaf arrangement: alternate; opposite

  • Leaf shape: lance

  • Ochrea: Not Present

  • Leaf margin: serrated; entire

  • Stem hairs: has hairs

  • Flower color: green; yellow

  • Growth habit: upright and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: has hairs

  • Flower symmetry: not symmetrical

  • Flower diameter: pencil

  • Root structure: fibrous; taproot

  • Leaf stalk: none