| Synonym | Author | CoL Status | Valid | Synonymy | Combination |
|---|---|---|---|---|---|
| Synthecium nanum | Fraser, 1943 | synonym | No | junior synonym |
original combination |
| Synthecium rectum | Nutting, 1904 | synonym | No | junior synonym |
original combination |
| Synthecium tubithecum | (Allman, 1877) | accepted name | Yes | senior synonym |
new combination |