This giant is the one people talk about.  You know it is in bloom when you see the yellow Canadian Goldenrod which grow along side it in bloom.  The Goldenrod is often falsely blamed for the allergies.   Here the male ragweed flowers are getting ready to spread their pollen (read allergens).

Giant Ragweed (Ambrosia trifida)

A closer view of the male inflorescence.

Giant Ragweed (Ambrosia trifida)

Here the tiny flowers can be seen.

Giant Ragweed (Ambrosia trifida) Male Blooms

Giant Ragweed (Ambrosia trifida) Male  Blossoms

These female flowers grow lower on the plant.

Giant Ragweed (Ambrosia trifida) Female Flower Clusters

A lower female flower for the production of seeds.

Giant Ragweed (Ambrosia trifida) Bract Cluster Containing Female Flowers

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