| Didymodon fallax (Hedw.) R.H. Zander, 1978 |
| Didymodon fallax var. fallax (Hedw.) R.H. Zander, 1978 |
| Didymodon fallax var. reflexus (Brid.) R.H. Zander, 1980 |
| Didymodon filicaulis Cardot, 1910 |
| Didymodon heribaudii Cardot, 1913 |
| Didymodon incrassatolimbatus Cardot, 1909 |
| Didymodon laevigatus (Mitt.) R.H. Zander, 1978 |
| Didymodon michiganensis (Steere) Saito, 1975 |
| Didymodon patentifolius Thér., 1931 |
| Didymodon revolutus (Cardot) R.S. Williams, 1913 |
| Didymodon rigidulus Hedw., 1801 |
| Didymodon rigidulus var. gracilis (Schleich. ex Hook. & Grev.) R.H. Zander, 1981 |
| Didymodon rigidulus var. icmadophilus (Schimp. ex Müll. Hal.) R.H. Zander, 1981 |
| Didymodon rigidulus var. rigidulus Hedw., 1801 |
| Didymodon rigidulus var. subulatus (Thér. & E.B. Bartram) R.H. Zander, 1981 |
| Didymodon stenopyxis Cardot, 1909 |
| Didymodon tophaceus (Brid.) Lisa, 1837 |
| Didymodon vinealis (Brid.) R.H. Zander, 1978 |
| Didymodon vinealis var. flaccidus (Bruch & Schimp.) R.H. Zander, 1978 |
| Didymodon vinealis var. luridus (Hornsch.) R.H. Zander, 1981 |