Naming and Classification of Fungi

Although it is something that we give little thought to, the naming and classification of objects play an important role in society. Imagine the problems that we would have if we were not given names and if we did not name our cities, streets or pets. Now imagine if we did not classify the books that are in our libraries, tools in hardware stores, video tapes in video stores, etc. Without names for objects and a system to classify them, it would be impossible or at least be very difficult to organize, categorize and find information for which we are searching. It should not be a surprise then that there is a discipline in biology called taxonomy that studies the classification and naming of organisms. Presently, there are approximately 1.5 million species of organisms that have been described by biologists and each year thousand of new species are described by science. It is estimated that the total number of species may range from 5 to 30 million. With such a rich diversity of life on this planet, naming and classifying this many organisms would be a difficult task, to say the least. However, such a system must be constructed if our knowledge in biology is to advance.

The job of the taxonomist is a difficult one. The general public thinks of them as snobbish because they refer to organisms with "fancy names". The reputation of the taxonomist is often not regarded in high esteem even among scientist because of its descriptive rather than experimental nature. Christensen (1961), a well respected mycologist-plant pathologist, describes taxonomist as "those who spend their time putting living things into pigeonholes, a low but necessary form of scientific endeavor". The lay person often wonders why taxonomist must refer to onions as Alium cepa or leopards as Panthera pardus. However, they are not using these names just to impress you or to make themselves feel more important in the eyes of their colleagues. Instead, they are merely identifying organisms by their scientific or species name. The species name is called a binomial, which consists of two parts. The first part is the genus (plural: genera) and the second is the specific epithet. For example, the species name for the human animal is Homo sapien. When written, the species name is emphasized by italicizing or underlining the binomial. Each known species, once it has been described by science, is given a unique species name. Another words, there is only one valid scientific name that is unique to a species regardless of where it may may be found. This differs from how society would name an organism. For example when we name our pets or children, the selected names are not unique. Afterall, how likely is it that anybody at this time would come up with an original, unique name. In taxonomy those types of names would be referred to as common names, which have been given to many species of organisms. It is not unusual for several common names to be applied to a single species and often a common name may be applied to several species. Although many well known species of organisms have common names, they are not officially used in science because of the confusion that they may cause. For example, the common name "Spanish Moss" is applied to at least two species of unrelated organisms in North America, Ramalina menziesii and Tillandsia usenoides. The former is a lichen, which represents a symbiotic relationship between a fungus and an alga and the latter is a flowering plant. Not only is this an example of a common name that applies to two different, unrelated species, but also one which is misleading since neither species is a moss nor is it Spanish. Conversely, Plantago major, a widespread weed, in Europe, is sometimes called "broad leafed plantain", but it also has at least 45 other English common names. Because the European countries speak a number of different languages, there are also 11 French names, 75 Dutch names, 106 German names and many more in other languages (Stern, 1997). Many of these common names may also apply to other unrelated plants. Nevertheless, because common names were the first names that many organisms received and are the names that the general population uses, it is unlikely that the less confusing species names will ever replace common names in our daily usage.

Although the usage of binomials seem to be a simple enough concept, its development took well over thousands of years. In summarizing the events that led to the binomial system, we will concern ourselves mainly with events having to do with plants because fungi as well as algae and bacteria were classified as plants until Whitaker (1969).

The concept of giving names to plants came about before civilization began, during the hunting and gathering period of mankind. For over a million years, during the Paleolithic (Old Stone) Age, this was how humans obtained food. At this time, there were small aggregations of families who were constantly wandering in search of game and plants. As the seasons changed and the animals they hunted moved on to greener pastures, the nomads followed, gathering plants as they wandered. The game that they hunted was the primary source of protein and the sugar, oils and vitamins were supplied by fruits, carbohydrates by roots and seeds and various plants for medicinal usage. Thus, it was important that early man recognized which plants could be used for these purposes, and just as important was the ability to determine which plants were poisonous. Those wanderers who were not able to make the distinction died and are not our ancestors. In addition to plants, mushrooms were undoubtedly collected. As you will see later, some species of mushrooms that were discovered during this period were thought to have had a major impact on future generations of humans.

The first names applied to plants were undoubtedly "local" common names. Because such names may be restricted to small communities, another nearby community would likely have a different common name for the same plant. This seems to be the likely mechanism by which numerous common names may have been applied to a single plant. The earliest known attempt at classifying plants was in the 3rd century B.C., by Theophrastus who classified approximately 500 species of plants into three categories: trees, shrubs and herbs, and utilized leaf and flower characteristics in distinguishing between different species.

A more applied scheme of classifying plants was devised around the 1st century A.D. Dioscorides, a Greek physician, classified plants according to their medicinal usage. He illustrated and described 600 species of plants in his most famous work, De Materia Medica. His books, which were highly respected, were frequently reproduced by hand-copying and became known as herbals. Unfortunately, there is such a thing as being too highly esteemed. The herbals became the sole source of medicinal information between 400 and 1400 A.D. It was considered heresy to speak against or to question information in the herbals, which resulted in few new ideas during this period of time. This was the period referred to as the Dark and Middle Ages, in Europe, and was the main reason the binomial species name took so long to develop.

A proliferation of knowledge occurred during the15th-17th century. This was, in part, due to new ideas that came about, but also had to do with the invention of the printing press by Johann Gutenberg (Figure 1), which made the mass reproduction of books possible. Prior to this invention, books were hand written. Thus, few books were available. At this time, new ideas came about because people began questioning the old knowledge of the ancients and began to look at plants to form their own ideas about them. This was the period of the herbalists who began to classify plant species according to their usage. This differed from the herbals in that the herbalist now classified plants not only for their medicinal usage, but also by their usage as food, clothing, as well as other applications. Included among these plants were also usage of some species of mushroom. Exploration ships often brought back new plants to be described. New medicinal plants were discovered at the same time. Thousands of new plants were recognized by various botanists during this period. The concept of classification, use of genera and origin of the binomial system of naming plants occurred at this time. The latter began with Gaspar Bauhin, in 1623, in Pinax theatri botanici, where he arranged plants according to species. However, this concept was not accepted until Linnaeus utilized it in 1754. The invention of the microscope led to introduction of new characteristics that could be used to identify plants.

During the 17th century, the use of Latin had become widespread in schools and universities and it became customary to give plants short Latin descriptions or phrase names in place of common names. These names began with a genus name followed by a short description consisting usually of no more than 12 words. For example, the spearmint plant was referred to as Mentha floribus spicatis, foliis oblongis serratis. In English, this would translate to "mint with flowers in a spike, leaves oblong and toothed". For obvious reasons, a phrase name was not practical for naming organisms. Can you imagine having to repeat the above scientific name each time reference was made to spearmint?

In 1753 Carolus Linnaeus introduced the use of binomial species names in his publication of Species Plantarum. This two volume publication was an ambitious effort to name and classify all of the known plants during Linnaeus' time. As with most taxonomist of his time, he used phrase names in recording the different species of plants that he recognized. However, Linnaeus added a shorthand notation for each species. In the left margin of each phrase name, he wrote a word, which, when combined with the genus, formed a convenient abbreviation for the phrase name. For example, "spicatis" was added to the margin of the phrase name for spearmint and "piperata" was added to peppermint (Fig. 2). The abbreviation for these species could then be referred to as Mentha spicatis and Mentha piperata, respectively. Other workers soon followed Linnaeus in recording species names in this fashion and eventually phrase names were replaced by binomials.

MENTHA.

spicata. 2. MENTHA floribus spicatis, foliis oblongis serratis.; Hort. ups. 168.; Mentha sylvestris, longioribus nigrioribus & minus in-; canis foliis. Baub. Pin. 227.
piperata. 4. MENTHA floribus capitatis, foliis lanceolatis serratis
subpetiolatis.
Mentha spicis brevioribus & habitoribus, foliis menthae
suscae, sapore servido piperis. Raj. angl. 3. p. 234
t. 10. f. 2.
Habitat in Anglia.

Fig. 2. Two species of Mentha from Species Plantarum with phrase names, and specific epithet at the left margin.

Today, all species names are binomials, and if cited formally, the name of the author who described the species or an abbreviation of the author's name is placed after the binomial, e.g. Mentha spicatis L. The "L." in this case credits Linnaeus as the person who first described this species. There are also variations as to how a person is credited after a species name. For example, in the supermarket mushroom, Agaricus bisporus (Lange) Imbach, Lange, whose name is in parentheses, was the original person who described the species. The parentheses indicate that the species was originally described in another genus. In this case the genus was Psalliota. Imbach, whose name appears after Lange, is credited with making the change from Psalliota to Agaricus. Therefore, if we wanted to find all of the literature that is available on this species, we would have to look under both Psalliota bisporus Lange and Agaricus bisporus (Lange) Imbach. There are various reasons for changing the name of a species and such notations allow us to trace these changes. Commonly, a name has to be changed because two species have the same name. Because of this and numerous other problems that can arise, there must be rules that govern the procedures for the naming of species as well as provisions for problems that may arise.

In discussing binomials, some mention has already been made concerning certain practices in the naming of species and their citations, i.e. the name is in Latin, it is underlined or italicized with the author of the species following the epithet. Although it is not obvious, a little thought on the subject should tell us that unless there is agreement, among taxonomists, concerning the method by which plants are named and classified, we can still expect confusion to reign. However, it would be over a hundred years before such an agreement was made. In 1867, 150 botanist, mostly from Europe and America, met in the First International Botanical Congress, to standardize the rules and regulations that would be used when plants are named. The rules adopted by these botanists are known as the International Code of Botanical Nomenclature (ICBN) and has been adopted by botanist throughout the world. The ICBN not only describes how species are named, but also when names must be changed, what names are unacceptable, how to validly publish a new species that you have just discovered and many other topics having to do with taxonomy of plants. The ICBN also governs the taxonomy of algae, bacteria and fungi. A similar, but different code was later adopted by zoologist.

When a new species of organism has been discovered, it must be given a Latin name and be published with a Latin description in order for the species name to be valid. Why Latin? Originally, Latin was used because it was the language of scholars, which made communications possible between individuals whose native language may differ. However, presently, few people in the sciences can speak or write Latin. So, why do we continue to use Latin? The main reason is because it is an unchanging language. This is important since contemporary languages are "dynamic". That is, they are constantly undergoing changes. Words often take on new connotations with time. For example, back in the 60's, when someone said "That's groovy". It was understood that you were referring to something that was really pretty neat. Today, I do not think that most people your age would know what that met. However, if I said "Hey, that's cool!", you would.