Species Identification and Naming: Why Photos and Names Are Not Safety Assurances

Urgent first. If anyone has eaten a wild mushroom and has vomiting, severe pain, confusion, a seizure or trouble breathing, call 911 or US Poison Help at 1-800-222-1222 right away. Do not wait for symptoms to settle and do not try to treat it at home. See poisoning: what to do first and plant and mushroom poisoning.

What this page is and is not. It explains names and taxonomy, the naming system scientists use. It is not an identification guide. It contains no descriptions of what any mushroom looks like, where it grows or how to tell species apart, and it will never tell you that a mushroom is safe to eat or use.

Why a photo or a name is not a safety assurance

Poisoning from wild mushrooms usually results from misidentification. [1] NIDA also warns of the risk of mistaking a toxic mushroom for one containing psilocybin. [2]

A poison-center case series from Wisconsin shows how easily this happens. It reviewed people who reported eating honey mushrooms (Armillaria), a group generally considered edible. Concern about mistaken look-alikes was common, and some cases that were reported as Armillaria were later identified as a psilocybin-containing Gymnopilus. [1] The authors note that the illness may be hard to tell apart from poisoning by amatoxin-containing species such as Galerina, and say early poison center or toxicology consultation can help with identification and management. [1]

Researchers do not always treat appearance alone as final. In a 2020 study of a mushroom from India, its appearance supported only a presumptive identification, and a DNA marker was used to show its close relationship to the genus Psilocybe. [3]

How scientists name fungi

• Binomial names. A species has a two-part Latin name, such as Psilocybe cubensis, followed by the person who described it, for example "(Earle) Singer".
• Synonyms. The same organism can carry older names. The GBIF Backbone Taxonomy lists Stropharia cubensis Earle as a synonym of the accepted name Psilocybe cubensis. [4] It lists Copelandia cyanescens among the synonyms of the accepted Panaeolus cyanescens. [5]
• Family placement changes. A 2021 paper placed Psilocybe in the family Strophariaceae, while the GBIF Backbone places the genus in Hymenogastraceae. [6][4] Different databases and papers may disagree for a time.
• Common names are not names. "Magic mushrooms", "liberty cap" or a strain name can mean different things in different places. For commercial names, see commercial mushroom names and naming limits.

Taxonomy is still unfinished

A 2024 genome study said that the phylogeny (family tree) and taxonomy of Psilocybe remain substantially incomplete, and that the psilocybin gene cluster is known for only five of about 165 species. [7] New species are still being described: in 2024, two new Psilocybe species from southern Africa were published, separated from their relatives by form and by DNA. [8]

The study also found that the ability to make psilocybin appears to have spread from Psilocybe to other mushrooms on four or five occasions. [7] That means psilocybin is not limited to one tidy group, and a name from one group does not rule it out in another. See other psilocybin-containing fungi.

How identification is done in laboratories

Laboratory identification uses DNA barcoding. An internal transcribed spacer (ITS) region is a DNA barcoding tool used for species identification, and a 2021 forensic method used it to distinguish Psilocybe cubensis from other fungi. [9] This is specialist work done on samples, not something a photo can replace.

Evidence labels used here

• Misidentification is a recognized cause of poisoning: established. [1]
• Reliable identification of a mushroom from a photo or a common name: Proper evidence not found. We found no source supporting it and many warning against it. [2]
• Taxonomy of Psilocybe: mixed, because it is still being revised. [7]

What to do instead

• Do not eat or use any wild mushroom on the strength of a photo, an app, a book or a name.
• If a mushroom has already been eaten and there are symptoms, call 911 or Poison Help first.
• For questions about a medical condition or medicines, speak with a licensed clinician. See talking with a health professional.

For the genus, see psilocybin mushrooms and the Psilocybe species directory.