| Common Name | Latin Name |
|---|---|
| Fall Panicum | Panicum dichotomiflorum |
| False Dandelion | see Common Catsear |
| Field Balm | see Calamint |
| Field Bindweed | Convolvulus arvensis |
| Field Dodder | see Dodder |
| Field Horsetail | Equisetum arvense |
| Field Madder | Sherardia arvensis |
| Field Pansy | Viola rafinesquii |
| Field Pennycress | Thlaspi arvense |
| Field Pepperweed | Lepidium campestre |
| Field Poppy | Papaver dubium |
| Field Violet | Viola arvensis |
| Fire Pink | Silene virginica |
| Fireweed | Erechtites hieracifolia |
| Flatweed | see Common Catsear |
| Florida Beggarweed | Desmodium tortuosum |
| Florida Betony | Stachys floridana |
| Florida Pusley | Richardia scabra |
| Flowering Spurge | Euphorbia corollata |
| Fogfruit | Phyla lanceolata |
| Fountain Grass | see Chinese Fountain Grass |
| Fourvalve Mimosa | see Sensitive Brier |
| Foxglove Penstemon | |
| Foxtail Barley | Hordeum jubatum |
| Foxtail Millet | Setaria italica |
| Frank's Sedge | Carex frankii |
| Frogfruit | see Fogfruit |
| Fuzzy Bean | see Missouri Fuzzy Bean |
