B
| Babiana |
| Baccharis |
| Baeckea |
| Ballota |
| Bamboos |
| Bambusa |
| Banksia |
| Baptisia |
| Bauera |
| Baumea |
| Begonia |
| Berberidopsis |
| Berberis |
| Bergenia |
| Beschorneria |
| Betula |
| Bidens |
| Billardiera |
| Billbergia |
| Blechnum |
| Bolax |
| Bomarea |
| Boronia |
| Bothriochloa |
| Bouteloua |
| Bravoa |
| Briza |
| Brugmansia |
| Brunnera |
| Buddleia |
| Bulbine |
| Bulbinella |