Toxic Fungi of Western North America

by Thomas J. Duffy, MD

Addendum 2: Fungal nomenclature, fungal taxonomy, and effect on fungal names

by Rodham Tulloss, PhD.

(This section has been modified by the author of Toxic Fungi of Western North America, Tom Duffy, to follow and flesh out the prior discussion of taxonomy. Any errors should be attributed to him.)

There are two complementary forces that end up producing a “currently correct name” in the life sciences in general. They play this role in mycology. One is nomenclature, which includes a set of rules governing the formation and publication of names in a way that is deemed valid by common agreement (the International Code of Botanical Nomenclature). The other is taxonomy as the study of the fungi in nature that bear (or eventually will bear) a valid name.

Nomenclature governs issues such as the set of rules for publishing a new name, the conditions under which a name may or may not be changed, the condtions under which a name can be changed in rank (a variety made into a species, for example), etc.

Taxonomy reveals the meaning behind a name and, consequently, causes names to disappear when two different names are found to belong to a single taxon.

Few fungi have common names and these names vary disconcertingly from area to area. The same common name may be used for different species (for example, in Nepal, the words meaning “devil’s apple” are applied both to a plant and a fungus) and more than one common name can be applied to a single species (for example, Jack-in-the-Pulpit and Lords-and-Ladies). Thus, for scientific communication purposes, there is a need for a more rigid designation. In the binomial system by the father of systematic botany, Linnaeus, each species is designated by two names. The first name is the name of the genus in the form of a noun and is always capitalized. The second name is called the species epithet and is in the form of an uncapitalized adjective or an uncapitalized noun serving as an adjective. Originally the names were largely limited to Latin and to Greek; however, currently pronounceable acronyms and even nonsense terms are permitted for epithets. There are a number of examples of epithets taken from Maori or aboriginal Australia.

Names get their meaning (even if it isn’t detailed at the time of naming) by having a type designated. For a species or a rank below species (such as variety or form), the type collection must be a preserved specimen. Methods are provided for replacing types if lost or destroyed or if they never existed (a problem with some old names). For a genus, the type is a species in that genus.

Some of the history of a name is preserved in the authorial citation that follows the name (usually the first time the name appears in a work).

When a newly described mushroom is published, the author(s) publishing the name get his/her/their names appended to the name of the newly recognized entity. An example that we can track through various times in its history is Amanita calyptrata Peck. Peck deposited a specimen from Oregon in the herbarium of what is now the New York State Museum. Let’s just call that “Peck’s type.”

Nomenclature leads to name changes if library research leads to an old, forgotten publication in which a name was used earlier than previously thought. For example, Agaricus citrinus Schaeff. was made invalid when an old Norwegian journal was found in which the combination Agaricus citrinus had been made by another author several years earlier than Schaeffer’s publication. This made “citrinus” unavailable or occupied at species rank. This led to the present day question of whether we should follow the core rules and stop using “Amanita citrina (Schaeff.) Pers.” or use the “rule for breaking the rule” and have a vote to conserve Schaeffer’s “Agaricus citrinus (and its subsequent “citrinus” transfer to the genus, Amanita).

To continue the calyptrata story…Several decades after Peck named Amanita caplytrata, W.A. Murrill, who followed the then existing American Code of Nomenclature, found that Lamarck had already used the combination Amanita calyptrata late in the eighteenth century. Following the rules of the time in America, Murrill changed Peck’s name. He recognized Venenarius as the oldest equivalent of Amanita and he picked lanei as his new species epithet. Peck’s type was still the type. So the equivalence of Murrill’s name to Peck’s name is guaranteed by definition. This kind of synonymy is called “nomenclatural synonymy”. Some authors indicate this by the 3 barred equivalence symbol (≡). Soon thereafter, Saccardo and Trotter, who did not recognize the American Code, changed the genus name of Venenarius to Amanita. This change gets recorded in the authorial citation as follows: Amanita lanei (Murrill) Sacc. & Trott.

Changes in the accepted code and within that code also lead to name changes that were not planned in advance, but are required by a newly approved version of the code. When a group of works of E.M. Fries were collectively assigned as the starting point of international mycological nomenclature, Lamarck’s “Amanita calyptrata” was made irrelevant because he published decades before the Friesian “starting point.” Back came “Amanita calyptrata” Peck as the correct name defined by Peck’s type.

When the starting point for fungi was moved back again to the canonical publication of Linnaeus, Lamarck became relevant again! Now we are caught up to the present day and the correct name of Peck’s type is, once again, Amanita lanei (Murrill) Sacc & Trott. Notice that all the changes in the correct name to be applied to Peck’s type had little to do with what the type was, what it looked like, what size or shape the spores had, etc. The changes all had to do with rules, changing between sets of rules, and changes to the rules themselves. All the names generated so far in our story are nomenclatural synonyms.

Now, let’s see how taxonomy plays its role. About the time that Murrill was following his American rules and creating Venenarius lanei, Ballen collected some large edible amanitas in California and posted them off with notes and photos to G.F. Atkinson at Cornell. Atkinson could not recognize the characteristics listed by Ballen as being those of anything previously named. In the fullness of time, there appeared a description of a proposed new species with a new name—Amanita calyptroderma G.F. Atkinson & Ballen. Decades went by before D.T. Jenkins looked at the Atkinson and Ballen type and Peck’s type, examined them, and proposed they were the same species. Those who have followed Jenkins, treat the name Amanita calyptroderma as an additional synonym to those we’ve met so far in this story. This time, however, the synonymy has everything to do with the study of the two types in detail. This time it is taxonomic synonymy. When there is a case of taxonomic synonymy, the older of the two names is the correct name. So here is a case of a name (Amanita calyptroderma) that is perfectly valid by nomenclatural rules alone, but succumbs to a physical review of the specimens that define two names.

Taxonomy can also lead to new names in other ways. The recognition of a taxonomic need for a new genus (say, Chroogomphus O.K. Mill.) will require the making of new combinations. Since Miller split Chroogomphus from Gomphus, species such as Gomphus vinicolor Peck became Chroogomphus vinicolor (Peck) O.K.Mill. This procedure is not automatic. Each name requires separate recombination. In our previous tale, Venenarius and Amanita were exchanged back and forth for purely nomenclatural reasons. In the present case, the originating motivation is taxonomic. However, since the type of Gomphus vinicolor Peck is also the type of Chroogomphus vinicolor (Peck) O.K. Mill., the two are nomenclatural synonyms.

Special abbreviations and other notations used in names and author citations are also worth understanding. Most readers of field guides are familiar with some abbreviations—those for species (sp. for the singular and spp. for the plural), the ranks below species (the infraspecific ranks): subspecies (subsp. or ssp.), variety (var.), and form (f). When someone proposes to change the rank of a species to a variety or a variety to a form, then this is another example of recombination. The author of the latest combination is placed to the right of parentheses as in the change of names of species in our earlier examples: Amanita pantherina var. pantherinoides (Murrill) Dav. T. Jenkins is a taxonomically motivated nomenclatural synonym of Amanita pantherinoides (Murrill) Murrill. [Murrill didn’t like having Saccardo and Trotter move all his species in Venenarius to Amanita, so he formed the habit of giving both names when he named a new species. Venenarius was the genus of choice for Murrill, but (for example, on the last page of an article) Murrill would say “for those who follow Saccardo” and list all his Venenarius species recombined as Amanita. [Thus Murrill achieved instantaneous name change, the fastest nomenclatural species sixgun in the West.]

When a name is being applied without certainty (a choice of the author), certain abbreviations may be inserted between the genus name and the species name. These follow idiosyncratic conventions (if any). These abbreviations can all be read as “close to (in my opinion, at least for the moment)”: ca., cf., affin.

There are also abbreviations that are sometimes seen embedded in authorial citations. Some have very specific uses associated with one or a very few authors, such as the colon preceding “Fr.” (meaning E.M. Fries). The name Amanita muscaria (L.:Fr.) Lam. Is an example of a sanctioned name. Names sanctioned by Fries are accepted no matter whether or not there is an older one for the same mushroom. This is a very special kind of nomenclatural provision. In the example, Linnaeus created the name Agaricus muscarius in his canonical, starting point work. Fries used the name (accepted it) in his set of books that are no longer the starting point for fungal names, but are the sanctioning works for agarics. Lamarck was the first known person to make the combination Amanita muscaria. This sanctioning applies to the epithet and not to the genus.