Common Ragweed, Ambrosia artemisiifolia

allergy ambrosia american annual asteraceae bitterweed blackweed carrot common compositae fever hay ragweed roman stammerwort stickweed tansy tassel weed wild wormwood allergen allergenic allergens allergies allergy artemisiifolia bloom blooms blossom blossoms botany exterior flora format inflorescence nature outdoor outdoors outside photo plant plants vertical