| | 1. Corolla 15–20 cm; calyx 8–12 cm, ribbed; seeds tan |
| D. wrightii |
| | 1' Corolla 4.5–16 cm; calyx 2–9 cm, angled or winged; seeds black or grayish brown |
| |
| | 2. Fruit nodding, prickles many, weak; stem grayish hairy |
| D. discolor |
| | 2' Fruit erect, prickles few, strong; stem glabrous to sparsely hairy |
| |
| | 3. Fruit prickles 8–22 mm; calyx 20–25 mm |
| D. ferox |
| | 3' Fruit prickles 3–10 mm; calyx 35–45 mm |
| D. stramonium
|