An epitype is a specimen or illustration selected to serve as an “interpretative type” when the holotype, lectotype, neotype or all original material of a name is demonstrably ambiguous and cannot be critically identified. The rules say the epitype must explicitly cite the type it supports (Madrid Code, Art. 9.9). It does not replace the original type; it sits beside it.
Epitypes are useful in fungi, where old dried type specimens can be hard to interpret. Psilocybe cyanescens is an example. Its name record lists a holotype, K(M) 63976, and an epitype, PRM 901481 (Species Fungorum), designated in a 2012 paper (Borovička, Rockefeller and Werner, 2012).
The word sometimes appears near commercial names, so the limits matter. An epitype anchors one scientific name to one reference specimen. It says nothing about any cultured line, label or product, and it is not a guide to recognizing a mushroom.
Sources
- Madrid Code (ICN, 2025), Art. 9.9
- Species Fungorum: Psilocybe cyanescens record
- Borovička, Rockefeller and Werner, 2012, Czech Mycology 64(2) (PDF)
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