| silphium compositum | | USA: District of Columbia; United States Botanic Garden, 100 Maryland Ave SW. | | 1243025567 |
| silphium compositum | | USA: District of Columbia; United States Botanic Garden, 100 Maryland Ave SW. | | 1243024427 |
| silphium compositum | | USA: District of Columbia; United States Botanic Garden, 100 Maryland Ave SW. | | 1243024053 |