Greater Ragweed - Giant Ragweed
Ambrosia trifida
Asteraceae (Composite Sunflower) Family

Greater Ragweed is a tall, rough, hairy annual with nodding heads of minute green flowers. Its preferred habitat is waste places, roadsides, fields and the margin of swampy areas. Distribution is throughout the Escambia region.

The leaves are large, opposite on the stem, palm-like in shape, 3-lobed and hairy.

The flowers are in elongated spikes similar to those of Common Ragweed. The male flowers are sparse on the spike (interrupted arrangement) while female flowers are in an uninterrupted spike. Flowers occur in the summer and autumn.

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

This plant is a giant among ragweed. Its pollen is spread by the wind and is a principal contributor to the irritation and cause of allergies and hay fever.

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