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Page 38 ï~~38 THE MICHIGAN BOTANIST Vol. 48 DEMYSTIFYING NOMENCLATURE: THE GAME OF THE NAME Edward G. Voss University of Michigan Herbarium 3600 Varsity Dr. Ann Arbor, Michigan 48108-2228 ABSTRACT Unlike "common names," which vary with region, language, and other circumstances, scientific names should be constant and applicable in all cultures for the same concept. Thus, they are Latin or treated as Latin, subject to the rules of that language and to the provisions of the International Code of Botanical Nomenclature regarding formation and proper original publication, as well as fixation of their application by designation of "types." KEY WORDS: Code, names, nomenclature, types T. S. Eliot (1939 p. 11) began one of my favorite poems: "The Naming of Cats is a difficult matter, it isn't just one of your holiday games;" The naming of plants is at least as difficult a matter. It's not exactly a holiday game, and for scientific names we do have to operate according to the rules. The present essay is intended as an introduction to and some background for a series of occasional discussions about "name changes" for certain of our familiar plants. I hope also to encourage proper use of terms that may be common words but have a specialized application in nomenclatural contexts. "Why are they always changing the scientific names of plants?" is a question often heard or muttered. There is sometimes even a complaint about divergent "common" names (which are in fact often merely attempts at literal translation of scientific names). So, first, a word about these. True common names-that is, in common use-vary with one's native language and even among traditions or usage within the same country. Plants that occur in countries with different languages or different uses will, of course, have different common names for the same plants. French Canadians will probably use different common names than do their anglophone countrymen. Even in the same language, there may be several or even many common names in truly common usage for a plant. Attempts at literal translation of scientific names are usually not truly common names. They may be English (or French, or Chinese) names but not in fact in common vernacular use. In contrast, Latin is a "dead" language, not official in any country, and there is a well-established Latin vocabulary for plant descriptions. Grammatical rules are stable. As the common language of scholars two and more centuries ago, Latin facilitated communication (for example, Linnaeus, a Swede, could readily communicate with scholars in other countries and rapidly earn his doctoral degree in Holland by writing in Latin). In order to validate publication of the name for a species, genus, variety, subspecies, etc. new to science, at least
Page 39 ï~~2009 THE MICHIGAN BOTANIST 39 a brief descriptive Latin diagnosis is now one of the requirements in the International Code of Botanical Nomenclature (ICBN)-of which the latest edition was authorized at the International Botanical Congress held in Vienna, Austria, in 2005. Although Latin as a language is relatively unchanging (except as modern concepts may require some form of Latinization for a new term), botanical science, like others, does change. There are internationally sanctioned "rules" in the Code, which governs the formation and application of scientific names of plants, but there can be no such "rules," internationally agreed upon, for what defines a species and other levels of classification. The rules of nomenclature deal with naming, not with science itself So when one of your favorite little wildflowers starts to appear in the literature under a different scientific name than the one you grew up with (and which for many people is the "right" name!), that generally means one or both of two things: (1) the long-familiar scientific name has been shown to be contrary to the rules of the International Code; or (2) the plant involved is believed (at least by some) to be more accurately classified in a way different than the familiar one-so of course the name may need to be different. For an example, consider the common "Threesquare" sedge long called Scirpus americanus by all who encountered it in marshes and on wet shores. When it was discovered that this name, as originally published, in fact applied to a different plant, the next oldest available name that applied to what had been termed Scirpus americanus turned out to be Scirpus pungens. So it became necessary to displace the well known name. One of the primary rules of nomenclature is the one of priority and pungens had priority of publication. More recently, botanists widely agree that this species and its closest relatives are different enough from Scirpus that they should be placed (classified) in a distinct genus. If this taxonomic position is accepted, then it becomes necessary to treat our common "Threesquare" as Schoenoplectus pungens. There is no rule against calling the plant Scirpus pungens but that indicates acceptance of a broader concept for the genus Scirpus than most current botanists who work with those plants accept. To summarize in a somewhat different way: nomenclature is based on certain rules, and is contingent: If something... then something.... The name depends on how the organism to be named is classified. The business of the botanist is to determine what needs a name: is it a distinct species, a variety or subspecies, merely a color form? In what genus-or is it sufficiently distinct to require recognition of a new genus? Once such taxonomic decisions have been made on the basis of scientific evidence, then the rules of nomenclature kick in to enable provision of a new name or application of an older previously published name if any. The whole matter is very much like any other aspect of language. What is a chair? A seat with four legs and a back? Without a back, would it be a stool? If it seats more than one person is it a bench? What covers everything called a chair? What do you call a piece of canvas supported by metal tubing with no distinction between seat and back? Words (and names) are applied to objects or concepts with some defining characters in common. You have a plant with
Page 40 ï~~40 THE MICHIGAN BOTANIST Vol. 48 parallel-veined leaves and with flowers that are bilaterally symmetrical and have an inferior ovary and a single cotyledon in the seed. So you correctly call it an orchid. Suppose you find in a remote tropical jungle a plant with flowers that look like those of an orchid. Does it belong to one of the nearly 20,000 species of orchids already described and named in over 700 genera, or is it new to science? If you conclude the latter (after a massive search in literature), then there are rules for publishing the name of a new species (and/or genus) according to the Code. Thus goes the distinction between taxonomy (science) and nomenclature. A word here about relevant adjectives: Some dictionaries (not to mention a great deal of sloppy usage) are confused regarding the distinction between "nomenclatural" and "nomenclatorial." "Nomenclatural" is an adjective derived from "nomenclature," which refers to the system of scientific names: their formation, proper publication, rules, and similar provisions for formation and use. The International Code of Botanical Nomenclature includes all these provisions and is revised at 6-year intervals during International Botanical Congresses. A "nomenclator" is a list or index or catalog of names-or a person who compiles such a list or catalog. "Nomenclatorial," then, is the proper adjective to refer to nomenclators and titles may even include an obvious reference, e.g., Nomenclator Zoologicus, which was published in 1939 to list all known generic names published for animals. The Index Kewensis is a series of volumes listing newly published names of plants; it is a nomenclator although that word does not appear in the title. THE NATURE OF SCIENTIFIC NAMES Almost everyone recognizes that the scientific name of a species of plant or animal consists of two words. The first is the name of the genus, and the second is termed by botanists the specific epithet (for it designates the particular species within its genus). Zoologists, who have their own Code, call the second word the species name but botanists insist that the species name is the full two words. This system of two-word designations for species was first applied consistently to all known (at least to him) plants (in 1753) and animals (in 1758) by the great Swedish naturalist, Carl Linnaeus. (Years later he was ennobled and then could be called von Linnd, a form preferred by many zoologists.) The 300th anniversary of Linnaeus' birth was celebrated in May of 2007. Many newspaper articles and other popular accounts declare that Linnaeus is remembered for his system of classification. This is not true! He is remembered for his system of naming, which is used throughout the world to this day. The generic name is always to be treated as a noun. The species epithet, however, may be an adjective modifying that noun, in which case it must agree with the gender of the generic name, according to the rules of Latin grammar. (Thus, we have the masculine Symphoricarpus albus for snowberry, the feminine Spiraea alba for meadowsweet, and the neuter Chenopodium album for lambsquarters.) Or the specific epithet may be a different noun (grammatically consid
Page 41 ï~~2009 THE MICHIGAN BOTANIST 41 ered to be in apposition with the generic name). The epithet in mullein, Verbascum thapsus, for instance, is an old classical name. Often the specific epithet is a genitive (possessive), either singular or plural, masculine or feminine. Thus we have Cirsium hillii for Hill's thistle (named for Rev. Ellsworth J. Hill); Crataegus coleae (a hawthorn named for Emma J. Cole, of Grand Rapids, Michigan); Rubus florenceae (a blackberry named for Florence N. [Mrs. Clarence R.] Hanes, of Kalamazoo County); and (in far northwestern North America) Potamogetom porsildiorum (named for the Canadian brothers Alf E. and Robert T. Porsild). The transfer of a species from one genus to another, therefore, may require changing the termination on an adjectival species epithet if the name of the new genus has a different gender in Latin. A potentially confusing name is borne by our pale dogwood: Cornus amomum subsp. obliqua, where the generic name is feminine (as were Latin names for trees ending in -us-which is usually a masculine ending), the species epithet is a neuter noun (an old Latin name in apposition), and the subspecies epithet a straightforward feminine adjective agreeing in gender with the generic name. There is, incidentally, no requirement of common sense that the species epithet be accurate if it refers to some aspect of the plant nor that, if it refers to a person, the person should have had some connection with discovery or understanding of the plant. A name or specific epithet may even be complete nonsense. The genus Filago, originally described by Linnaeus and referring to thread-like hairs, led to four anagrams when that genus was split up by Cassini, a 19th century French specialist on Compositae, who named segregate genera for certain of the species: Gifola, Ifloga, Logfia, and Ogilfa. These are validly published names, whether or not one accepts the "splitting" classification that they represent. The frequent advice that one can learn something about the characteristics or origins of plants from their names is also less than universal truth. Under the Code, names may not be rejected merely because they are inappropriate, offensive, or even inaccurate, When Linnaeus named Asclepias syriaca, the common milkweed, a native of North America, he thought that it had come from Syria. Similarly, Impatiens capensis, our common touch-me-not or jewelweed, was erroneously thought to have originated at the Cape of Good Hope in Africa. Geographical concepts of Virginia, Carolina, Canada, and other places were often rather vague to European botanists in the 18th Century. ["Virginia" at one time extended west to the Mississippi and it has been noted that Linnaeus ascribed nothing to any area in North America between "Virginia" and "Canada".] Similarly, we may not reject the epithet in Lycopus uniflorus merely because in fact plants of that species bear more than one flower! It is customary, in formal usage, to follow the name of a taxon (a unit of classification at any level (species, variety, family, etc.) with the name or names of the person(s) who authored that scientific name. Much popular lore notwithstanding, the names of authors are not part of the scientific name. The botanical and the zoological codes both declare that the name of a species consists of two words; the name of the genus and the epithet for the species. The name(s) of its authors may optionally be added after or following it! Authors'
Page 42 ï~~42 THE MICHIGAN BOTANIST Vol. 48 names, which are usually abbreviated if long or well known, often provide a helpful quick bibliographic clue as to where the name might have been published, and when. They also distinguish between homonyms, that is, identical names published by different authors. For example, a common dune willow is Salix cordata Michx., indicating that it was named by the French botanist Andrd Michaux in his pioneering flora of North America published in France in March of 1803. Unfortunately, the American botanist G. H. E. Muhlenberg published the name Salix cordata at least two months later in 1803-but for an entirely different willow (now known as Salix eriocephala Michaux). S. cordata Muhl. being a later name identical to Michaux's, even though applied by him to a different species, is said to be "illegitimate," i. e. contrary to the rules (see below). Note that we are talking of authors of published works that include names. The author of a name is not necessarily an "authority," i. e. an expert or specialist on the plants involved: their identification, distribution, family or other relationships, DNA, cultivation, etc. VALID OR LEGITIMATE? One sometimes reads of a "valid species," an unfortunate use of that word. For example, the journal BioScience, in two places in 2005, used careless language in this regard: "Unlike other disciplines, in which species described according to the rules remain valid until determined invalid by further research,"... and "species formerly synonymous". Names, not species, may be synonymous! The Code considers a name to be "valid" or "validly published" if its publication meets all of the several requirements for publication of a new name, including (currently) at least a brief Latin diagnosis or description and designation of a type (see below). On the other hand, a "legitimate" name is a validly published one that also meets certain requirements for usage, e.g., not a homonym (e.g. Salix cordata Muhl.) of an identical prior one, is not antedated by another name applied to the same taxon, nor is it described with reference to a prior name that ought to have been adopted (i.e., is not "superfluous"). Deciding whether something is a "good" or acceptable species (or genus, etc.) is a scientific or taxonomic judgment, not a nomenclatural one. But one does first have to decide, on a scientific basis (position, rank, and circumscription are the key scientific issues), what needs a name before its proper nomenclatural disposition can be determined. SYNONYMS Often one hears of "synonyms" without realizing, perhaps, that there are two basic kinds in nomenclature. "Taxonomic synonyms" (or as the zoologists call them, "subjective" synonyms) are two or more different names published for the same organism at the same rank (such as genus or species). Ordinarily the oldest name to be published at the same rank is the one to be used; the later synonym (sometimes called by zoologists a "junior" synonym), even if validly
Page 43 ï~~2009 THE MICHIGAN BOTANIST 43 published, is illegitimate (see above). On the other hand, "nomenclatural synonyms" (termed by zoologists "objective synonyms") are two or more names that are based on the same type (see below)-usually through error or else by change in rank (e, g., recognizing a subspecies or variety at the rank of species). TYPES One of the most frequently misunderstood aspects of nomenclature is the function of types. A type is not simply a representative specimen of some kind that illustrates a species or other taxon. That is, it's not necessarily "typical" in the variational sense of the word. It is a very special specimen, however, that determines application of a name-even if it turns out to have been an extreme variant within the species to which it belongs. Many species when first named as new to science were not well enough known for the namer to be aware of the full range of variation of the taxon. But it is now obligatory to specify a type, an individual specimen to which the name applies. And the name will also apply to all other specimens that one deems to belong to the same taxon. The role of a type is very aptly expressed in the excellent work by Jeffrey (1973, p. 19): "It is not the purpose of a type to be typical in the variational sense; the purpose of a type is to provide a fixed point associated with a name in the range of variation of organisms so that no matter where discontinuities are found to occur and boundaries between taxa drawn, the application of the name can be objectively and unequivocally decided." In other words, a name cannot be applied in such a sense that its type would be excluded. So types are very important in applying and retaining names when taxa are split and in interpreting intentions of prior authors; they thus contribute to stability in nomenclature. The type concept is relatively new (20th century) and retroactive designation of types for older names that lack them does help to reduce confusion in nomenclature. Most large herbaria keep their types in designated cabinets where they will receive minimal routine handling and maximum care in case of emergency. Finally, remember that it is names, not taxa, that have types. There is no such thing as the "type of a species." ACKNOWLEDGMENTS I am grateful to Rogers McVaugh for first instilling in me a fondness for nomenclatural issues and to the many colleagues from around the world who sustained that interest while serving on the Editorial Committee for the International Code of Botanical Nomenclature during the years (1969-1993) that I was secretary or chairman of that committee. SELECTED REFERENCES Bailey, L. H. (1933). How Plants Get Their Names. Macmillan, New York. 161 pp. [Reprinted 1963 by Dover Publ.] Eliot, T. S. (1939). Old Possum's Book of Practical Cats. Faber & Faber, London. 46 pp.
Page 44 ï~~44 THE MICHIGAN BOTANIST Vol. 48 Jeffrey, Charles. (1977). Biological Nomenclature. 2nd ed. Edward Arnold, London. 72 pp. McNeill, J., et al. (2006). International Code of Botanical Nomenclature (Vienna Code). Regnum Vegetabile Vol. 146. xviii + 568 pp. Ride, W. D. L., et al. (1999). International Code of Zoological Nomenclature. International Commission on Zoological Nomenclature. xxix + 306 pp. Stearn, William T. (1966). Stearn's Dictionary of Plant Names for Gardeners. A Handbook on the Origin and Meaning of the Botanical Names of Some Cultivated Plants. Cassell, London. 363 pp.