Historically, the naming of living things was given scientific structure in the mid-eighteenth century by the Swedish naturalist Carl von Linné (Linnaeus). He is credited with devising the binomial system which gives living organisms a two-part Latin name: a generic name, followed by a specific name, or epithet. He included descriptions and names of a few fungi in his Species Plantarum in 1753. At that time Latin was the common tongue of educated people throughout Europe, especially the aristocracy and clergy. The system was universally accepted and is still in use today. The understanding of fungi was vastly improved by the studies of C. H. Persoon in Holland and those of the Swedish botanist, Elias Fries. Persoon’s work included especially the Gasteromycetes, rusts and smuts and he published lists of these fungi in 1801. Fries was the leading authority of the day on the agarics and other microfungi and macrofungi and his work was first published in 1821. These two publications of Persoon and Fries are regarded as critical in the naming of these respective groups of fungi; they either confirm or over-ride the original names of Linnaeus and others who published between 1753 and 1801 or 1821. Persoon and Fries have the status of ‘sanctioning’ authors. Authorship of names is indicated by the use of internationally agreed abbreviated forms for the names of authors; these are written after the Latin names of the fungi where precision is required.
To give an example, the fungus we know as the Fly Agaric was named Agaricus muscarius by Linnaeus and he is credited by the addition of L. after the name. Elias Fries accepted the specific epithet muscarius in 1821 and he is credited by the addition of ‘:Fr.’. C.H. Persoon gathered together from Linnaeus’s broad grouping of Agaricus those species which he recognised as having some features in common and placed them in a new genus Amanita Pers. in 1797. The abbreviation Pers. following the generic name gives him credit for creating the new genus. He subsequently transferred the Fly Agaric into this genus and named it Amanita muscaria.
Currently, therefore, the scientific name of the Fly Agaric can be written Amanita muscaria (L.:Fr.) Pers. Note that the bracketed term relates to the specific epithet, and the abbreviation that follows applies to changes to the generic name. The terms after the Latin name are the ‘author citation’. A similar example is given by Amanita crocea (Quél.) Kühner & Romagn. This tells us that Quélet introduced the epithet crocea and that Kühner & Romagnesi later placed it in the genus Amanita. Note that it is convention to start the generic name with a capital letter, but in modern usage the specific epithet is always written in lower case, even when an individual is honoured, e.g. Agaricus bernardii.
Biological nomenclature has four sets of rules, for animals, for plants, for bacteria and, recently, for viruses, and these differ in detail. In the 19th century the Botanical Rules were adopted for all kinds of fungi, and this continues to be so, even though it now appears that, in their evolutionary history, fungi are more closely related to animals than to green plants. The naming of both plants and fungi is controlled by the International Code of Botanical Nomenclature. This Code is subject to modification at six year intervals at meetings of the International Botanical Congress. To comply with the International Code any newly discovered species of plant or fungus has to be given a Latin (or latinized) binomial together with a description or diagnosis in Latin. Another rule is that the ‘Rule of Priority’ applies – that is, when two names have been used at different times for the same fungus the name first validly published usually prevails. Since 1953 a further requirement is that the Latin description must relate to a ‘type specimen’ stored in an indicated herbarium. At first sight these rules seem straightforward, so one might ask “Why do names keep changing?”