| Datura stramonium | Jimsonweed |
| Daucus carota | Wild Carrot |
| Decodon verticillatus | Swamp Loosestrife |
| Delphinium ajacis | Doubtful Knight's-spur |
| Dendrolycopodium obscurum | Tree Clubmoss |
| Dennstaedtia punctilobula | Hay-scented Fern |
| Dentaria heterophylla | Slender Toothwort |
| Dentaria laciniata | Cutleaf Toothwort |
| Deparia acrostichoides | Silvery False Spleenwort |
| Descurainia sophia | Herb-sophia |
| Desmodium canadense | Showy Tick-trefoil |
| Desmodium ciliare | Hairy Small-leaved Tick-trefoil |
| Desmodium dillenii | Perplexed Tick-trefoil |
| Desmodium glabellum | Dillen's Tick-trefoil |
| Desmodium nudiflorum | Bare-stemmed Tick-trefoil |
| Desmodium paniculatum var. paniculatum | Panicled-leaf Tick-trefoil |
| Desmodium perplexum | Perplexed Tick-trefoil |
| Dianthus armeria | Deptford-pink |
| Dianthus barbatus | Sweet-william |
| Dicentra cucullaria | Dutchman's Breeches |
| Dichanthelium oligosanthes var. scribnerianum | Scribner's Witch Grass |
| Dichanthelium scoparium | Broom Witch Grass |
| Dicranum scoparium | Windswept Broom Moss |
| Diodella teres | Well-drained Buttonweed |
| Diodia teres | Well-drained Buttonweed |
| Diodia virginiana | Poorly-drained Buttonweed |
| Dioscorea villosa | Yellow Yam |
| Diospyros virginiana | Persimmon |
| Dipsacus fullonum | Fuller's Teasel |
| Dipsacus sylvestris | Fuller's Teasel |
| Dirca palustris | Eastern Leatherwood |
| Draba verna | Spring Draba |
| Drosera intermedia | Spoon-leaved Sundew |
| Dryopteris marginalis | Marginal Wood-fern |
| Duchesnea indica | Indian Cinquefoil |
| Dysphania ambrosioides | Wormseed Goosefoot |