| Incertae sedis |
| Incertae sedis |
| Incertae sedis |
| Incertae sedis |
| Incertae sedis |
| Incertae sedis |
| Incertae sedis |
| Incertae sedis |
| Incertae sedis |
| Intercalarispora J. L. Crane & Schokn., 1983 |
| Intercalarispora nigra J. L. Crane & Schokn., 1983 |
| Isthmolongispora Matsush., 1971 |
| Isthmolongispora variabilis Matsush., 1975 |
| Isthmotricladia Matsush., 1971 |
| Isthmotricladia gombakiensis Nawawi, 1975 |
| Ityorhoptrum P. M. Kirk, 1986 |
| Ityorhoptrum verruculosum (M. B. Ellis) P. M. Kirk, 1986 |
| Junewangia W. A. Baker & Morgan-Jones, 2002 |
| Junewangia globulosa (Tóth) W. A. Baker & Morgan-Jones, 2002 |
| Junewangia lamma (Whitton, McKenzie & K. D. Hyde) W. A. Baker & Morgan-Jones, 2002 |