| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Aa | 1 | 0 | 0 |
| Aa achalensis Schltr. | 0 | 0 | 1 |
| Aa fiebrigii (Schltr.) Schltr. | 0 | 0 | 1 |
| Aa hieronymi (Cogn.) Schltr. | 0 | 0 | 1 |
| Aa weddelliana (Rchb. fil.) Schltr. | 0 | 0 | 1 |
| Abatia | 1 | 0 | 0 |
| Abatia stellata Lillo | 0 | 0 | 1 |
| Abatus Troschel 1851 | 1 | 0 | 0 |
| Abatus cavernosus (Philippi 1845) | 0 | 0 | 1 |
| Abderitidae | 1 | 0 | 0 |
| Abelichnus | 1 | 0 | 0 |
| Abelichnus astigarrae Calvo 1991 | 0 | 0 | 1 |
| Abelisauridae | 1 | 0 | 0 |
| Abelisaurus Bonaparte 1984 | 1 | 0 | 0 |
| Abelisaurus comahuensis Bonaparte 1984 | 0 | 0 | 1 |
