Common Ragweed
Ambrosia artemisifolia Linnaeus
Asteraceae (Composite Sunflower) Family

Giant Ragweed
Ambrosia trifida - Linnaeus

Common Ragweed is an upright, much branched, annual with a taproot. Preferred habitat is roadsides, old fields, waste places, pond and marsh margins, sand and gravel beaches. Distribution is throughout the Escambia region.

Leaves are deeply dissected; the lower ones opposite and upper alternate on the stem; light green in color and up to four inches long. Lower leaves have a tendency to dry and curl.

Flowers are separate male and female. Male flowers are small yellow-green and packed with yellow stamens borne in heads of 15-20 florets each; arranged in slender clusters near the top of the plant. Female flowers are small; green and stalkless; borne in small clusters at the leaf axil. Flowers occur in the summer

Fruit is achene (a seed which outer layer is fused to it).


Giant Ragweed is similar to the above except the plant is a larger annual with angled stems.  The leaves are opposite on the stem, deeply palmately lobed on lower leaves and no lobes on the upper.  Leaf margins are serrate and the surface is scrufy hairy.  Flowers are abundant in slender racemes.  The plant is also known as horse-cane and richweed.

Ragweed pollen is airborne, carried by the wind. Consequently, people who suffer severe allergies are prone to dreadful ailments during its flowering season. Unfortunately, the goldenrod is blamed for this malady. Goldenrod pollen is carried by insects and thus has nothing to do with hay fever or allergies unless the pollen is sniffed directly from the flower.

Dog Fennel, whose flower is quite similar to ragweed, has a leaf that is thinly dissected into hair-like segments.

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