A genus (plural genera) is the rank above species. Every species name begins with its genus, so Psilocybe cubensis and Psilocybe semilanceata are two species in the genus Psilocybe. Under the naming code, the type of a genus name is the type of one of its species (Madrid Code, Art. 10.1).
Genera are hypotheses about relationships, and they move. DNA showed the old Psilocybe was two lineages, so the non-bluing species were assigned to Deconica (Norvell, 2009). In 2019 part of Inocybe was split off into new genera such as Inosperma (Species Fungorum).
Psilocybin is not confined to one genus. A 2022 laboratory survey lists seven mushroom genera with psilocybin-producing members: Psilocybe, Panaeolus, Pluteus, Gymnopilus, Pholiotina, Galerina and Inocybe (Gotvaldová et al., 2022). In each genus outside Psilocybe only a small share of species is involved, and several of these genera also contain poisonous species. Belonging to a genus says nothing about whether a mushroom is safe.
Sources
- Madrid Code (ICN, 2025), Art. 10.1
- Norvell, 2009, Mycotaxon 110
- Gotvaldová et al., 2022, International Journal of Molecular Sciences
- Species Fungorum: Inosperma calamistratum record
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