Giant ragweed vegetative
Giant ragweed |
Giant ragweed vegetative
| Scientific Name | Ambrosia trifida L. |
| Other Names | Iron-weed, great ragweed, wild hemp, horse-weed, and bitterweed.. |
| Life Cycle | summer annual |
| General Description | Erect, tall plant with large distictively three-lobed leaves. |
| Seedlings | Cotyledons are round, oblong, and thick (3-5x larger than common ragweed). Young leaves are opposite and covered in rough hairs. First pair of leaves are unlobed, but have large teeth on the margins (possibly small lobes). |
| True Leaves and Stem | Stems and leaves are rough and hairy. Leaves are opposite and divided into three lobes. Lower leaves are more deeply lobed that upper leaves. Petioles are winged on the margins. |
| Roots | Primarily fiberous, but shallow taproot may be present. |
| Flower and Fruit | Flowers produce large amounts of pollen. Flowers are small, green, inconspicuous, and found on the ends of branches. Fruits have several longitudinal ridges ending in 5 short spines (cimilar to a crown). Seeds are approximately 6-12mm long (2x the size of common ragweed seeds). |
| Other Information | Pollen is the main cause of hay fever. |