FamilyBiddulphiaceae
| Taxon: | Rank: |
| Alveoflexus | genus |
| Ancoropsis | genus |
| Arcusidiscus | genus |
| Biddulphia | genus |
| Biddulphiopsis | genus |
| Euodiella | genus |
| Hydrosera | genus |
| Medlinia | genus |
| Neohuttonia | genus |
| Pseudotriceratium | genus |
| Stoermeria | genus |
| Terpsinoë | genus |
| Trigonium | genus |