A species is the basic rank in the naming of living things. Its name is a binary combination: the name of the genus followed by a single specific epithet (Madrid Code, Art. 23.1). In Psilocybe cubensis, Psilocybe is the genus and cubensis the epithet. Each name is tied to a type specimen, which fixes what it refers to.
Naming a species and placing material in it are different steps. In a 2025 study, 12 of 42 samples had a species by appearance that differed from their DNA classification (Cohen et al., 2025). A 2022 check of museum specimens found their Psilocybe names largely unreliable (Bradshaw et al., 2022).
Species are also how the counts get made, and the counts disagree. Gastón Guzmán’s 1983 world monograph accepted 144 Psilocybe species out of 467 names considered (Guzmán, 1983); a 2022 study put true Psilocybe at about 165 (Bradshaw et al., 2022). Labels such as Golden Teacher are not species; they are informal names for material within one.
Sources
- Madrid Code (ICN, 2025), Art. 23.1
- Cohen et al., 2025, Scientific Reports (PMC)
- Bradshaw et al., 2022, Applied and Environmental Microbiology
- Guzmán, 1983, The Genus Psilocybe (Internet Archive)
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