| Asterella P. Beauv., 1805 |
| Asterella bolanderi (Austin) Underw., 1895 |
| Asterella californica (Hampe) Underw., 1895 |
| Asterella dominicensis S.W. Arnell, 1958 |
| Asterella echinella (Gottsche) Underw., 1895 |
| Asterella elegans (Spreng.) Trevis., 1874 |
| Asterella lateralis Howe, 1898 |
| Asterella palmeri (Austin) Underw., 1895 |
| Asterella pringlei Underw., 1895 |
| Asterella venosa (Lehm. & Lindenb.) A. Evans, 1920 |
| Aytonia J.R. Forst. & G. Forst., 1776 |
| Aytonia crenulata (Gottsche) Underw., 1895 |
| Aytonia evansii Haynes |
| Aytonia intermedia (Lindenb. & Gottsche) Kuntze |
| Aytonia rupestris J.R. Forst. & G. Forst. |
| Aytonia wrightii (Sull.) Underw. |
| Aytoniaceae Cavers, 1911 |
| Cryptomitrium Austin ex Underw., 1883 |
| Cryptomitrium tenerum (Hook.) Austin ex Underw., 1884 |
| Fimbraria Nees, 1809 |