| Balechina Loebl. & A.R. Loebl. III, 1968 |
| Balechina coerulea (Dogiel) F.J.R. Taylor, 1976 |
| Basidiodendron Rick, 1938 |
| Basidiodendron cinereum (Bourdot & Galzin) Luck-Allen, 1963 |
| Batrachochytrium Longcore, Pessier & D. K. Nichols, 1999 |
| Batrachochytrium dendrobatidis Longcore, Pessier & D. K. Nichols, 1999 |
| Batrachochytrium salamandrivorans Martel, Blooi, Bossuyt & Pasmans, 2013 |
| Belemnospora P. M. Kirk, 1981 |
| Belemnospora navicularis R. F. Castañeda & Heredia, 2000 |
| Beltrania Penz., 1882 |
| Beltrania concurvispora Matsush., 1975 |
| Beltrania malaiensis Wakef., 1931 |
| Beltrania onirica Lunghini, 1981 |
| Beltrania rhombica Penz., 1882 |
| Beltraniopsis Bat. & J. L. Bezerra, 1960 |
| Beltraniopsis esenbeckiae Bat. & J. L. Bezerra, 1960 |
| Beltraniopsis ramosa R. F. Castañeda, 1985 |
| Beltraniopsis tanzaniensis Piroz., 1972 |
| Bisporella Sacc., 1884 |
| Bisporella citrina (Batsch) Korf & S. E. Carp., 1974 |