| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Acanthoica Lohmann 1903 | 2 | 0 | 0 |
| Acanthoica aculeata | 0 | 0 | 2 |
| Acanthoica quattrospina | 0 | 0 | 4 |
| Acanthostomella Jörgensen 1927 | 0 | 0 | 2 |
| Achnanthaceae | 1 | 0 | 0 |
| Achnanthales | 1 | 0 | 0 |
| Achnanthes Bory de Saint-Vincent 1822 | 1 | 0 | 0 |
| Achnanthes longipes C. Agardh 1824 | 0 | 0 | 2 |
| Actinocyclus Ehrenberg 1837 | 1 | 0 | 6 |
| Actinocyclus adriaticus | 0 | 0 | 2 |
| Actinoptychus Ehrenberg 1843 | 2 | 0 | 2 |
| Actinoptychus senarius | 0 | 0 | 4 |
| Actinoptychus undulatus | 0 | 0 | 4 |
| Alexandrium Halim 1960 | 0 | 0 | 2 |
| Algirosphaera Schlauder 1945 | 1 | 0 | 0 |
