| betula nigra | | USA: District of Columbia; US Botanical Garden, Washington | | 1243025729 |
| betula nigra | | USA: District of Columbia; US Botanical Garden, Washington | | 1243024675 |
| betula nigra | | USA: District of Columbia; US Botanical Garden, Washington | | 1243024228 |
| betula nigra | | USA: District of Columbia; US Botanical Garden, Washington | | 1243023791 |