| Ptilothamnionopsis P.S. Dixon, 1971 |
| Ptilothamnionopsis lejolisea (Farlow) P.S. Dixon, 1971 |
| Spermothamnion Aresch., 1847 |
| Spermothamnion gorgoneum (Mont.) Bornet, 1896 |
| Spermothamnion gymnocarpum M. Howe, 1920 |
| Spermothamnion investiens (P. Crouan & H. Crouan) Vickers, 1905 |
| Spermothamnion macromeres Collins & Herv., 1917 |
| Spermothamnion repens (Dillwyn) Rosenv., L.K., 1924 |
| Spermothamnion repens var. variabile (C. Agardh) Feldm. -Maz., 1941 |
| Spermothamnion snyderae Farlow, 1899 |
| Spermothamnion speluncarum (Collins & Herv.) M. Howe, 1920 |
| Spongoclonium Sond., 1853 |
| Spongoclonium caribaeum (Børgesen) M.J. Wynne, 2005 |
| Tiffaniella Doty & Meñez, 1960 |
| Tiffaniella gorgonea (Mont.) Doty & Meñez, 1960 |
| Tiffaniella phycophila (W.R. Taylor) Gordon, 1972 |
| Tiffaniella saccorhiza (Setch. & N.L. Gardner) Doty & Meñez, 1960 |
| Tiffaniella snyderae (Farlow) I.A. Abbott, 1971 |
| Wrangelia C. Agardh, 1828 |
| Wrangelia argus (Mont.) Mont., 1856 |