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In addition to Linneaus-inspired taxonomies of the botanical world, I suppose there are some other proposals for different kinds of taxonomic accounts, perhaps for specific sub-domains of botany or perhaps historical. I'd be keen to learn about those.
Additionally, if any of you know there are some other alternative non-taxonomic approaches to botanic classification that are widely-used in sub-domains or in the early days of science, I'd be keen. I guess there are still some "common sense" classification to be made between use (ornamental/non-ornamental; medicinal/edible/poisonous), but perhaps there's more.
The most common alternative to taxonomic classifications are functional classifications. Emphasizing ecological similarities rather than similarities in relatedness, they can be regarded as complementary approach to, but not as a replacement of taxonomy. Why do we need this? Because species often perform very similar tasks, exhibit very similar characteristics and, most importantly, are very, very numerous (there are ~ 300,000 vascular plants). Reducing this redundant complexity is crucial for decision-making in conservation politics or the projection of vegetation change under future climatic conditions (Woodward & Cramer, 1996).
The idea behind this is to use functional traits, such as seed size, height, photosynthetic pathway, root density, etc., as a surrogate of a species' ecological 'role' -- its response to environmental factors and its impact on ecosystems. Seed mass for example (functional trait), is a proxy for the dispersal ability of a plant (function, performance). You should have a look at Lavorel et al. (2007), there is a nice table (too big to include here) that links specific traits to the actual ecological functions they describe. But look at this figure from the same paper:
By applying multivariate statistics like cluster analyses or ordination methods, species can then be classified into functional types. To make up one example, a functional type that might emerge from species with the following traits
- height: > 20 m
- seed size: > 0.5 cm
- woody: yes
- Specific leaf area: low
would certainly represent climax forest trees. This classification does not distinguish between individual species, because, from an ecosystem perspective, they all are functionally roughly equivalent.
For further research google 'Functional trait', 'Plant functional type' or have a look at refs 3 and 4.
- Woodward, F. I. and Cramer, W. (1996): Plant functional types and climatic change: introduction. Journal of vegetation science, 7(3): 306-308.
- Lavorel, S., Díaz, S., Cornelissen, J. H. C., Garnier, E., Harrison, S. P., McIntyre, S., Pausas, J. G., Pérez-Harguindeguy, N., Roumet, C., and Urcelay, C. (2007): Plant Functional Types: Are We Getting Any Closer to the Holy Grail? In: Canadell, J. G., Pataki, D. E., and Pitelka, L. F. (editors): Terrestrial Ecosystems in a Changing World, Global Change-The IGBP Series, pages 149-164. Springer Berlin Heidelberg.
- Halloy, S. (1990): A morphological classification of plants, with special reference to the New Zealand alpine flora. Journal of vegetation science, 1(3): 291-304.
- Leishman, M. R. and Westoby, M. (1992): Classifying plants into groups on the basis of associations of individual traits-evidence from Australian semi-arid woodlands. Journal of Ecology, 80: 417-424.
From Aristotle to Linnaeus: the History of Taxonomy
The system that we still use today for giving scientific names to plants and animals has many founders, from the Greek philosopher Aristotle to the Swedish physician and botanist Carolus Linnaeus.
Taxonomy is the study of scientific classification, in particular the classification of living organisms according to their natural relationships. Taxonomy's first father was the philosopher Aristotle (384-322 BC), sometimes called the "father of science." It was Aristotle who first introduced the two key concepts of taxonomy as we practice it today: classification of oranisms by type and binomial definition.
Aristotle was the first to attempt to classify all the kinds of animals in his History of Animals (Historia Animalium in Latin). He grouped the types of creatures according to their similarities: animals with blood and animals without blood, animals that live on water and animals that live on land. Aristotle's view of life was hierarchical. He assumed that creatures could be grouped in order from lowest to highest, with the human species being the highest. Subsequent commentators on Aristotle interpreted this as a "ladder of nature" (scala naturae) or a "Great Chain of Being," but these were not Aristotle's terms. His system of classification was not evolutionary, and the various species on the ladder had no specific genetic relationship to each other. Aristotle regarded the essence of species as fixed and unchanging, and this view persisted for the next two thousand years.
His other innovation was binomial definition. "Binomial" means "two names," and according to this system each kind of organism can be defined by the two names of its "genus and difference." The word "genus" comes from the Greek root for "birth," and among its meanings are "family" and "race." Aristotle's notion of definition was to place every object in a family and then to differentiate it from the other members of that family by some unique characteristic. He defined humans, for example, as the "rational animal." This, according to Aristotelian thought, defines the essence of what it is to be human, as opposed to such pseudo-definitions as "featherless biped."
But what Aristotle did not do was methodically use binomial definition in his system of biological classification. This innovation had to await the development of modern science after the Rennaissance.
Aristotle's influence was profound and long-lasting. Much of his work has not survived to the present day, so that we don't know the details of his study of plants, but his student Theophrastus (372-287 BC) continued it, becoming known as the "father of botany." He is believed to have planted the first botanical garden on the grounds of Aristotle's Lyceum. Most of the text of his two botanical works, On Plants (De Historia Plantarum) and The Causes of Plants (De Causis Plantarum) still exists, although only in Latin translations. The first describes the anatomy of plants and classifies them into trees, shrubs, herbaceous perennials, and herbs. The second work discusses their propagation and growth and served in part as a practical guide to farmers and gardeners. However, he introduced no new principles of classification.
After Aristotle, there was little innovation in the fields of the biological sciences until the 16th century AD. At this time, voyages of exploration were beginning to discover plants and animals new to Europeans, which excited the interest of natural philosophers, as scientists were then called. There was great interest in naming these new species and fitting them into the existing classifications, and this in turn led to new systems of classification. Many of the botanists of this period were also physicians, who were interested in the use of plants for producing medicines.
Andrea Cesalpino (1519-1603) was an Italian physician who created one of the first new systems of classifying plants since the time of Aristotle. He was a professor of materia medica, the study of the preparation of medicines from plants, at the University of Pisa, and was also in charge of the university's botanical garden. There, he wrote a series of works titled On Plants (De Plantis), detailing his system of classification. While his work was in large part based on the work of Aristotle and his successors, his innovation in basing his system of classifying plants on the basis of the structure of their fruits and seeds influenced subsequent scientists such as Linnaeus.
One botanist who was influenced by Cesalpino was Gaspard Bauhin (1560-1620), a Swiss physician and anatomist. In his 1623 Illustrated Exposition of Plants (Pinax Theatri Botanica), he described about six thousand species and gave them names based on their "natural affinities," grouping them into genus and species. He was thus the first scientist to use binomial nomenclature in classification of species, anticipating the work of Linnaeus.
By the time Carl (Carolus) Linnaeus (1707-1778) was born, there were many systems of botanical classification in use, with new plants constantly being discovered and named. This, in fact, was the problem &mdash there were too many inconsistent systems, and the same plant might have several different scientific names, according to different methods of classification.
During his childhood, Linnaeus was so fond of collecting plants that he was known as "the little botanist." He later became a physician, as so many other early taxonomists did, but returned to botany as his primary study.
He published his most innovative work as a young man in 1735. The System of Nature (Systema Naturae) is notable for an overall framework of classification that organized all plants and animals from the level of kingdoms all the way down to species. The full subtitle of its tenth edition was: System of nature through the three kingdoms of nature, according to classes, orders, genera and species, with characteristics, differences, synonyms, places. This system of classification, although greatly modified, is essentially the one we use today.
Linnaeus followed this work with The Genera of Plants and The Species of Plants, setting out a system of plant classification based on the structure of flower parts, in which he was influenced by Cesalpino. This method, in which plants were grouped together according to the number of stamens in their flowers, for example, was not accurate, but it was easy to use and thus readily adapted by scientists who were continually discovering more new varieties of plants. Linnaeus himself undertook much work in the field, and he was even more influential through his students, whom he sent around the world to gather specimens.
His major works went through a great deal of revision in his lifetime, eliminating errors and coming closer to the system that was eventually adopted by taxonomists worldwide. His methods of classifying plants have been completely superseded by a deeper scientific understanding. Originally, Linnaeus had only used binomial nomenclature to classify plants, but he later extended this system to include animals and even minerals. There were also errors, subsequently corrected. At first, for example, he had placed the whales among the fishes, but later moved them into the mammals. He was also the first taxonomist to place humans among the primates (or Anthropomorpha) and to give them the binomen Homo sapiens.
If Linnaeus is now considered the father of taxonomy, his success rested on the work of his predecessors. He was the first, in his System of Nature, to combine a hierarchical system of classification from kingdom to species with the method of binomial nomenclature, using it consistently to identify every species of both plants and animals then known to him.
While he continued throughout his lifetime to revise and expand this great work, so his successors have continued to revise the principles of taxonomy, now according to genetic principles, informed by the analysis of DNA. So it always is with science: we stand on the shoulders of our predecessors, always reaching higher.
Show/hide words to know
Fossil: the hardened remains, or an impression of remains of an organism that existed in a past geological age. more
Latin: language spoken in ancient Rome and still used today for many scientific terms and names. more
Species: typically a group of organisms that are so similar that they can interbreed (have offspring). more
Illustration from The Life-Story of Insects, by Geo. H. Carpenter
Have you ever wondered how animals and plants get their names? People give them names, lots of different names! Even the simple cockroaches you see either inside of buildings or outside in their usual damp dark protected places have more than one name.
Even though roaches aren’t popular, their fossils show us that these successful insects have been on Earth for more than 300 million years. There are about 3,500 different kinds of roaches living today. One of these cockroaches, the Oriental cockroach, is found throughout the world and has a whole bunch of names.
Some of its many names are “waterbug” or a “black beetle,” but it isn’t either a bug or a beetle. Some animals and plants may have as many as six or more common names, and some of these are misleading. If you want to know whether you and another person are talking about the same insect, you need to use the scientific name, Blatta orientalis. When you write the name, you use italic letters to show that you’re using the scientific name. “Blatta” is a Latin word meaning “cockroach”, and “orientalis”, also Latin, means “east.” Many scientific names use Latin words, but some use Greek words. The word “cockroach” comes from the Spanish word, “cucaracha.”
Linnaean System of Classification Definition
Carl Linnaeus is considered the father of modern ecology and the father of taxonomy. Although many philosophers and scientists began the work of biological classification before him, his work in particular provided a foundational system for sorting and conceptualizing living organisms that has lasted since the 1700s.
Modern scientists have proposed and implemented a number of changes to Linnaean classification in order to account for ever-expanding knowledge of the evolutionary and genetic relationships between species. Much of Linnaeus’ system was removed or altered, in fact, except for the kingdom Animalia.
Linnaeus’ scientific legacy lies most of all in his introduction of a hierarchical system of biological classification, as well as the use of binomial nomenclature.
A Few Bad Scientists Are Threatening to Topple Taxonomy
Imagine, if you will, getting bit by an African spitting cobra. These reptiles are bad news for several reasons: First, they spit, shooting a potent cocktail of nerve toxins directly into their victims’ eyes. But they also chomp down, using their fangs to deliver a nasty bite that can lead to respiratory failure, paralysis, and occasionally even death.
Before you go rushing to the hospital in search of antivenin, you’re going to want to look up exactly what kind of snake you’re dealing with. But the results are confusing. According to the official record of species names, governed by the International Commission of Zoological Nomenclature (ICZN), the snake belongs to the genus Spracklandus. What you don’t know is that almost no taxonomists use that name. Instead, most researchers use the unofficial name that pops up in Wikipedia and most scientific journal articles: Afronaja.
This might sound like semantics. But for you, it could mean the difference between life and death. “If you walk in [to the hospital] and say the snake that bit you is called Spracklandus, you might not get the right antivenin,” says Scott Thomson, a herpetologist and taxonomist at Brazil’s Museum of Zoology at the University of São Paulo. After all, “the doctor is not a herpetologist … he’s a medical person trying to save your life.”
In fact, Spracklandus is the center of a heated debate within the world of taxonomy—one that could help determine the future of an entire scientific field. And Raymond Hoser, the Australian researcher who gave Spracklandus its official name, is one of the forefront figures in that debate.
By the numbers, Hoser is a taxonomy maven. Between 2000 and 2012 alone, Hoser named three-quarters of all new genera and subgenera of snakes overall, he’s named over 800 taxa, including dozens of snakes and lizards. But prominent taxonomists and other herpetologists—including several interviewed for this piece—say that those numbers are misleading.
According to them, Hoser isn’t a prolific scientist at all. What he’s really mastered is a very specific kind of scientific "crime": taxonomic vandalism.
To study life on Earth, you need a system. Ours is Linnaean taxonomy, the model started by Swedish biologist Carl Linnaeus in 1735. Linnaeus’s two-part species names, often Latin-based, consist of both a genus name and a species name, i.e. Homo sapiens. Like a library’s Dewey Decimal system for books, this biological classification system has allowed scientists around the world to study organisms without confusion or overlap for nearly 300 years.
But, like any library, taxonomy is only as good as its librarians—and now a few rogue taxonomists are threatening to expose the flaws within the system. Taxonomic vandals, as they’re referred to within the field, are those who name scores of new taxa without presenting sufficient evidence for their finds. Like plagiarists trying to pass off others' work as their own, these glory-seeking scientists use others’ original research in order to justify their so-called “discoveries.”
“It’s unethical name creation based on other people’s work,” says Mark Scherz, a herpetologist who recently named a new species of fish-scaled gecko. “It’s that lack of ethical sensibility that creates that problem.”
The goal of taxonomic vandalism is often self-aggrandizement. Even in such an unglamorous field, there is prestige and reward—and with them, the temptation to misbehave. “If you name a new species, there’s some notoriety to it,” Thomson says. “You get these people that decide that they just want to name everything, so they can go down in history as having named hundreds and hundreds of species.”
Taxonomic vandalism isn’t a new problem. “Decisions about how to partition life are as much a concern of politics and ethics as of biology,” two Australian biologists wrote in a June editorial in the journal Nature on how taxonomy’s lack of oversight threatens conservation. They argued that the field needs a new system, by which the rules that govern species names are legally enforceable: “We contend that the scientific community’s failure to govern taxonomy … damages the credibility of science and is expensive to society."
But the problem may be getting worse, thanks to the advent of online publishing and loopholes in the species naming code. With vandals at large, some researchers are less inclined to publish or present their work publicly for fear of being scooped, taxonomists told me. “Now there’s a hesitation to present our data publically, and that’s how scientists communicate,” Thomson says. “The problem that causes is that you don’t know who is working on what, and then the scientists start stepping on each other’s toes.”
Smithsonian.com spoke with some of these alleged vandals, and the scientists trying to stop them and save this scientific system.
In 2012, Hoser dubbed this species Oopholis adelynhoserae. According to other taxonomists, it is actually the New Guinea crocodile, Crocodylus novaeguineae. (Wikimedia Commons)
If you’re a scientist who wants to name a newly discovered form of life, your first step is to gather two to three lines of evidence—from DNA and morphology, for example—that prove that you’re dealing with something new to science. Then you have to obtain a holotype, or an individual of the species that will serve as an identifier for future researchers. Next you’ll write up your paper, in which you describe your discovery and name it according to taxonomic naming conventions.
Finally, you send your paper off to a scientific journal for publication. If you are the first to publish, the name you’ve chosen is cemented into the taxonomic record. But that last step—publication—isn’t easy. Or at least, it isn’t supposed to be. In theory, the evidence you present must adhere to the high scientific and ethical benchmark of peer-review. Publication can take months, or even years.
However, there’s a loophole. The rules for naming a new animal taxon are governed by the ICZN, while the International Association for Plant Taxonomy (IAPT) governs plants. And while the ICZN requires that names be published, as defined by the commission’s official Code, “publishing” doesn’t actually require peer-review.
That definition leaves room for what few would call science: self-publishing. “You can print something in your basement and publish it and everyone in the world that follows the Code is bound to accept whatever it is you published, regardless of how you did so,” Doug Yanega, a Commissioner at the ICZN, told me. “No other field of science, other than taxonomy, is subject to allowing people to self-publish.”
Thomson agrees. “It’s just become too easy to publish,” he says.
Why not? When the Code was written, the technologies that allow for self-publishing simply didn’t exist. “The Code isn’t written under the assumption that people would deliberately try to deceive others,” Yanega says. But then came the advance of desktop computing and printing, and with it, the potential for deception.
Moreover, the ICZN has no actual legal recourse against those who generate names using illegitimate or unethical science. That’s because the Code, which was last updated in 1999, was written to maintain academic freedom, Yanega says. As the Code reads: “nomenclatural rules are tools that are designed to provide the maximum stability compatible with taxonomic freedom.”
Vandals have zeroed in on the self-publishing loophole with great success. Yanega pointed to Trevor Hawkeswood, an Australia-based entomologist accused by some taxonomists of churning out species names that lack scientific merit. Hawkeswood publishes work in his own journal, Calodema, which he started in 2006 as editor and main contributor.
“He has his own journal with himself as the editor, publisher, and chief author,” Yanega says. “This is supposed to be science, but it’s a pile of publications that have no scientific merit.” (In response to questions about the legitimacy of his journal, Hawkeswood delivered a string of expletives directed towards his critics, and contended that Calodema has “heaps of merit.”)
Raymond Hoser also owns his own journal, the Australasian Journal of Herpetology (AJH). AJH has faced similar criticism since it was launched in 2009, despite claims by Hoser that the journal is peer-reviewed. “Although the AJH masquerades as a scientific journal, it is perhaps better described as a printed ‘blog’ because it lacks many of the hallmarks of formal scientific communication, and includes much irrelevant information,” wrote Hinrich Kaiser, a researcher at Victor Valley College in California, and colleagues in the peer-reviewed journal Herpetological Review.
Publications like these let bad science through, taxonomists say. According to them, vandals churn out names of so-called “new species” in their journals, often when the scientific evidence to support a discovery is lacking. And if the names are properly constructed and accompanied by characteristics that are “purported” to distinguish the species, they become valid under the Code. “As long as you create a name, state intention that the name is new, and provide just the vaguest description of a species, the name is valid,” Scherz says.
Hoser, for his part, doesn’t see a problem. “People complain that we name too much stuff,” he told me. “But that’s bullsh*t. There’s a lot out there.”
Like a phylogenetic tree, a cladogram illuminates relationships between groups of animals. (Wikimedia Commons)
Taxonomic vandalism usually isn't subtle. Oftentimes, vandals will explicitly steal others’ science to support their so-called "discovery," taxonomists told me. "They don’t do any of the research, they don’t own any of the research,” as Thomson puts it. One of the most common lines of evidence they steal is what's known as the phylogenetic tree.
Phylogenetic trees, not unlike family trees, reveal how different animal specimens are related to each other based on their genetics specimens that are genetically similar are grouped together. In some cases, those groupings represent species that have yet to be named, which scientists call “candidate species.” Researchers commonly publish phylogenetic trees on the road to discovering a new species, and then use those published trees as evidence for that species’ uniqueness.
However, gathering enough evidence to make a discovery can take months or even years. Meanwhile, culprits like Hoser swoop in. Once the tree is publically available, vandals use it as evidence to justify a “discovery,” which they quickly publish in their personal journals. “Vandals go through literature and comb through phylogenetic trees, find a group in the phylogenetic tree that could be named, and quickly give it a name,” Scherz said.
It’s difficult to pinpoint the total number of species named by vandals, but Thomson estimates there are tens of thousands. Hoser readily admits that he has used this approach to name tens—if not hundreds—of taxa. “I managed to name about 100 genera [of snakes] by basically looking at phylogenetic trees,” Hoser said. Among them was the African spitting cobra, Spracklandus.
Another approach is based on a theory called “allopatric speciation,” or the evolution of new species through geographic isolation.
The theory states that when animal populations are physically separated without opportunities to interbreed, they can grow genetically distinct. Over time, the populations can become separate species—meaning, in simplistic terms, that they can’t successfully reproduce with each other. This is a widely-accepted theory, but not proof in itself. Without DNA samples and a detailed examination of several individuals from each population, it’s not so much a discovery as it is a clue.
Taxonomic vandals have been known to take full advantage of this theory to make “discoveries,” says Kaiser. To find and name new species, they will search for geographic barriers that cut through the range of an existing species, such as rivers or mountains. If the species populations look different on either side of the barrier—on one side they’re red and on the other side they’re blue, for example—vandals will automatically declare them two separate species.
“Taxonomic vandals are saying that these are two separate…[species]…but they really have no scientific underpinning of that statement,” Kaiser said of this approach. Hoser, Kaiser writes, uses both existing phylogenetic trees and allopatric speciation to justify generating "new" species names.
For his part, Hoser maintains that the distinctions are often self-explanatory. “Sometimes it's so bloody self-evident that you don't need to resort to molecular-f***ing-genetics and DNA to work out the difference,” Hoser said. “It's like working out the difference between an elephant and a hippopotamus—they’re obviously different animals. You don’t need to be a Rhodes Scholar to figure out the difference.”
His colleagues disagree. “He puts the name on straight away without any evidence,” says Thomson of Hoser. “It’s like throwing darts at a dart board with his eyes closed, and every now and then he hits a bull’s-eye.”
In 2009, Hoser petitioned the ICZN to redefine the lethal Western Diamondback rattlesnake (Crotalus atrox) as the holotype for a new genus he proposed naming "Hoserea" after his wife. He was declined. (Rolf Nussbaumer Photography / Alamy)
While the ICZN doesn’t have the power to regulate these problems, that doesn’t mean individual taxonomists are sitting quietly by.
The scientific community often opts collectively to reject the names that vandals ascribe, even if they’re technically Code-compliant, according to several taxonomists I spoke with. Strictly speaking, this is against the rules of the Code—the names are official, after all. But according to Wolfgang Wüster, a herpetologist at Bangor University, many herpetologists “are scientists first and nomenclaturists second.”
Kaiser, Wüster and other taxonomists have been leading the fight to stamp out vandalism within herpetology. “The scientific community currently appears almost unanimous in their approach not to use Hoser’s nomenclature,” Wolfgang Denzer, a herpetologist, wrote in a critical review of Hoser’s conquests in the open access, peer-reviewed journal Bonn zoological Bulletin.
As stated, many herpetologists refuse to use the name Spracklandus, a name they say is a product of vandalism. Instead they use Afronaja, the name coined by scientists who first published data, which, taxonomists say, Hoser scooped. Unfortunately, this results in what taxonomists call “parallel nomenclature”: when a single taxon is known by more than one name.
Parallel nomenclature is exactly what the Code was intended to prevent.
And for good reason. Confusion created by parallel nomenclature complicates any process that depends on unambiguous species names, such as assigning conservation statuses like “Endangered” or “Threatened.” As the authors write in the Nature editorial, how a species is classified by taxonomists influences how threatened it appears, and thus how much conservation funding it’s likely to receive. As the authors of the editorial write: “Vagueness is not compatible with conservation.”
Parallel nomenclature could also make it more difficult to acquire an export permit for research, taxonomists say. “If you are in one country that uses vandalistic names and try to export an animal, your import and export permits won’t match, which means animals get held up when you cross borders,” Thomson said.
These kind of detrimental consequences—for science and conservation—are why some scientists are calling for a more dramatic solution: revising the Code itself.
A table of "amphibia" from Carl Linnaeus' Systema Naturae. (Carl Linnaeus / Wikimedia Commons)
The boycott against Hoser’s names remains widespread and “undeniably effective,” Yanega says. So effective, in fact, that Hoser submitted a request to the ICZN in 2013, in which he asked the commission to publicly confirm the validity of the name Spracklandus—a name that is already valid by the rule of the Code.
“He was upset by the boycott,” Yanega says, adding that Hoser was seeking validation from the commission.
“The Commission is asked to rule on these seemingly routine matters because widely promulgated recommendations by some herpetologists to use … Afronaja … instead has resulted in instability in nomenclature,” the case reads.
But the case isn’t just about one genus, one name, and one vandal, say the taxonomists I spoke to. “It’s a test of not only which names are going to stand, but also a test—which is how I see it and my colleagues see it—of scientific integrity,” Kaiser says.
It’s still unclear which way the commission will rule, Yanega says. “It depends on how objective we have to be and how well-phrased the question is before us.” If the question, which is still formulating through internal debate, is whether Hoser’s name is destabilizing taxonomy—that is, phrased as a technical, but not ethical, question—the commission will likely rule against him, Yanega adds.
But it’s possible that the scales may tip the other way, Yanega says. And if they do tip in favor of Hoser, herpetologists I spoke to said that they would have no choice but to abandon the Code altogether. “The rumors among herpetology are that if the Commission rules in Hoser’s favor, then it’s over,” Sherz said. “Then we drop the Code and make our own, because it just can’t work like this.”
The authors of the Nature editorial offer up a solution: move the code under a different purview. Specifically, they suggest that the International Union of Biological Sciences (IUBS)—the biology branch of the International Council for Sciences—should “take decisive leadership” and start a taxonomic commission. The commission, they propose, would establish hardline rules for delineating new species and take charge in reviewing taxonomic papers for compliance. This process, they say, would result in the first ever standardized global species lists.
"In our view, many taxonomists would welcome such a governance structure,” the authors write. “Reducing the time spent dealing with different species concepts would probably make the task of describing and cataloguing biodiversity more efficient.”
But, barring that, a revision of the Code is unlikely to happen anytime soon, Yanega told me. Because the ICZN strives to act in everyone’s best interest, any change requires consensus across the taxonomic community. “Everything is done with some level of cooperation and consensus,” he said. “We would indeed be willing to change the rules, if we could ever get the community to come to a consensus as to how the rules should be changed.” So far, that hasn’t happened.
Part of the problem is that most branches of taxonomy aren’t impacted as heavily as herpetology, where many prominent vandals operate. That’s because herpetology is home to thousands of undescribed species, so there’s plenty of low hanging fruit for vandals to pick. Moreover, “herpetology maybe does attract more interesting characters than other branches of science,” says Wüster. “Reptiles are kind of pariahs of the animal world”—as are some of the people who study them, it would appear.
“Other disciplines within taxonomy don’t have the same sorts of problems with these same sorts of people,” Yanega says. If scientists who study birds and fish, for instance, are less exposed to the problem of vandalism, they’re not going to support a stricter Code, he adds: “To them, it sounds like you're being dictatorial or practicing censorship.”
But, at least to the herpetologists I spoke to, that’s a price that researchers should be willing to pay for good science. “This is a compromise where we might have to give up some academic freedom for the sake of the community,” Kaiser says. “This crime needs to be weeded out.”
Plant Taxonomy: A Historical Perspective, Current Challenges, and Perspectives
Taxonomy is the science that explores, describes, names, and classifies all organisms. In this introductory chapter, we highlight the major historical steps in the elaboration of this science, which provides baseline data for all fields of biology and plays a vital role for society but is also an independent, complex, and sound hypothesis-driven scientific discipline.In a first part, we underline that plant taxonomy is one of the earliest scientific disciplines that emerged thousands of years ago, even before the important contributions of the Greeks and Romans (e.g., Theophrastus, Pliny the Elder, and Dioscorides). In the fifteenth-sixteenth centuries, plant taxonomy benefited from the Great Navigations, the invention of the printing press, the creation of botanic gardens, and the use of the drying technique to preserve plant specimens. In parallel with the growing body of morpho-anatomical data, subsequent major steps in the history of plant taxonomy include the emergence of the concept of natural classification , the adoption of the binomial naming system (with the major role of Linnaeus) and other universal rules for the naming of plants, the formulation of the principle of subordination of characters, and the advent of the evolutionary thought. More recently, the cladistic theory (initiated by Hennig) and the rapid advances in DNA technologies allowed to infer phylogenies and to propose true natural, genealogy-based classifications.In a second part, we put the emphasis on the challenges that plant taxonomy faces nowadays. The still very incomplete taxonomic knowledge of the worldwide flora (the so-called taxonomic impediment) is seriously hampering conservation efforts that are especially crucial as biodiversity has entered its sixth extinction crisis. It appears mainly due to insufficient funding, lack of taxonomic expertise, and lack of communication and coordination. We then review recent initiatives to overcome these limitations and to anticipate how taxonomy should and could evolve. In particular, the use of molecular data has been era-splitting for taxonomy and may allow an accelerated pace of species discovery. We examine both strengths and limitations of such techniques in comparison to morphology-based investigations, we give broad recommendations on the use of molecular tools for plant taxonomy, and we highlight the need for an integrative taxonomy based on evidence from multiple sources.
Keywords: Classification DNA Floras History Molecular taxonomy Molecular techniques Morpho-anatomical investigations Plant taxonomy Species Taxonomic impediment.
What Did Carolus Linnaeus Contribute to Science?
The University of California Museum of Paleontology at Berkley states that Carolus Linnaeus, also known as Carl von Linné and Carl Linnaeus, is often called the "Father of Taxonomy" for his system of naming, ranking and classifying organisms. He is also known as the founder of binomial nomenclature.
Linnaeus classified living organisms as being from either the plant or animal kingdom. Each kingdom was divided into smaller groups referred to as classes. Each class was divided into orders. Every order was split into genera. Each genus divided into species, and each division was made based upon specific features.
Linnaeus described 4,300 species of animals in his 1735 book "Systema Naturae" and 5,000 species of plants in his 1737 book, "Geenera Plantarum" This classification system, with its many additions, revisions and modifications, is used worldwide.
Linnaeus' other significant scientific contribution was his system of binomial nomenclature. This system gives a scientific name consisting of two words to every plant and animal species. The first word describes the name of the genus, while the second word denotes the name of the species. Scientists throughout the world continue to use this system.
Linnaeus was born in Sweden on May 23, 1707, and he died on Jan. 10, 1778 in Uppsala. He studied botany at Uppsala University. He later explored the Swedish Lapland and studied medicine in Holland. It was during his studies in Holland that Linnaeus first developed his classification system and binomial nomenclature.
Advantages of the Sharper Diagnosis of Type Material
A key advantage of molecular diagnoses is their utility for more precisely characterizing type material than is possible with morphological traits. The better a type collection (including syntypes and paratypes) is characterized, the more reliable the identification of future specimens. This does not mean that unidentified specimens in the future will need to be sequenced for identification. Instead, identification may continue to rely on morphological matching of preserved specimens or, increasingly, of images using machine learning. Having stringent diagnoses that specify DNA differences among closely related species (or subspecific taxa) can facilitate identification in those cases where the correct identification of a specimen is crucial, for example, for parasites of crops or of animals, especially us, but also for specimens that are incomplete, poorly preserved, or immature, so that diagnostic features are missing. Also, as pointed out by Cook et al. (2010), it is often quicker and cheaper to use diagnostic DNA features than to rely on the traditional expert-centered paradigm of identification.
The many studies that have clarified erroneous application of names or relationships among living and extinct species by sequencing DNA from type material attest to the importance of DNA diagnosis, now and in the future ( Stuart and Fritz 2008 Hausmann et al. 2009 Sebastian et al. 2010 Stuckas and Fritz 2011 Stuckas et al. 2013 Fritz et al. 2014 Petzold et al. 2014 Heupink et al. 2014 Cappellini et al. 2014 Renner et al. 2014 Speidel et al. 2015 Erpenbeck et al. 2016).
Easy Accessibility, Interpretability, and Utility in Automated Keys
Several taxonomic journals have hypertext markup language that allows direct linkages between new species names and sequences in GenBank or other sequence databanks ( Penev et al. 2010). Sequences mentioned in diagnoses will serve as a standard for future reference, as pointed out by Reynolds and Taylor (1991) and Tautz et al. (2003), together with the type material deposited in one or, better, more museum collections (cf. the Darlington quote at the top of this paper). “DNA sequence information is digital and is not influenced by subjective assessments. It would be reproducible at any time and by any person, speaking any language. Hence, it would be a universal communication tool and resource for taxonomy, which can be linked to any kind of biological or biodiversity information. Even if a query sequence does not produce an exact match, it will be possible to link an organism to closely related ones” ( Tautz et al. 2003, p. 71). These authors, therefore, proposed that an attempt be made to provide a DNA sequence alongside all future taxonomic samples and species descriptions. In my view, this should become a recommendation in all Codes. Taxonomists, however, have begun to go further by including DNA characters directly in the diagnosis of nominal new taxa. This makes the type material more valuable and is safer for the future than if sequences come from other specimens that may be less well-preserved than type material typically is (or should be). Most importantly, sharp diagnosis of the types of species names will help avoid the publication of unnecessary names (new synonyms).
Last, DNA sequence databases with automated matching can replace identification keys. The functionality of such species-naming pipelines has been demonstrated in fungi ( Koljalg et al. 2013). For animals, the concept of a Barcode Index Number (BIN) has been proposed ( Ratnasingham and Hebert 2013), namely a persistent, species-level taxonomic registry using patterns of nucleotide variation in the barcode region of the cytochrome c oxidase I (COI) gene. The system begins by examining the correspondence between groups of specimens identified to species through prior taxonomic work and those inferred from the analysis of COI sequence variation using several algorithms.
Differences Between Barcoding and DNA-Based Diagnosis, and How the Two Approaches Will Increasingly Reinforce Each Other
There are three differences between barcoding and using DNA features in the protologs of new species. First, barcoding relies on a few universally agreed markers DNA-based diagnosis does not, but can instead use a mix of other DNA traits, even indels (cf. Table 1). Second, barcoding is about identifying unknown material by matching sequences to named sequences in a database. This is not the purpose of DNA-based diagnoses, which serve to better describe a new species’ type collection(s). For barcoding, one does not need to study type material or deposit a type in a designated public collection, as one does to name a species. Third, barcoding one’s material is not a requirement or recommendation in any of the Codes of Nomenclature, while diagnosis is a recommendation in all of them, providing the foundation for the view advocated here, that two or three examples of DNA-based diagnoses (perhaps from Table 1) be added to encourage the use of DNA-based diagnoses.
One of the early criticisms of DNA barcoding (identifying species with DNA sequence markers) originated from the misconception that it was equivalent to DNA taxonomy, and as pointed out by a reviewer of this Point of View, it may be important to stress that I am arguing here for a (continued) modification in how we diagnose types, hence, an aspect of nomenclatural work, not in how we circumscribe species, which is a matter of taxonomy, not nomenclature.
Genetic Distance Less Suitable than Diagnostic Substitutions?
Tripp and Lendemer (2012) have raised the question whether node-based diagnoses ( Hibbett et al. 2011 Kirk 2012), rather than diagnostic substitutions, are valid and have submitted a request to the Nomenclature Commission (for plants and fungi) for clarification of two examples involving fungal names published without reference to specific characters distinguishing them from their closest relatives (see above, “Results” section for a specific example, Rhizoplaca polymorpha). Based on my reading of 98 molecular diagnoses, I agree with Tripp and Lendemer that discrete DNA features of type specimens are more useful than node-based diagnoses, which focus on phylogenetic context, not specimens. At least one study, however, has combined genetic distances and discrete trait states ( Meyer-Wachsmuth et al. 2014), and the naming of bacteria has long relied on distances (see section “Materials and Methods”).
In practice, the two terms are often used interchangeably to refer to the study of relationships among organisms,which in turn often derives from their description and drives their naming.
The history of the disciplines of systematics and taxonomy has shifted with the evolution over the years of the state of knowledge about living organisms, their origins, and their relationships. There has been a historical shift from an emphasis on classification (simply naming and identifying organisms) to the study of phylogenetic (evolutionary) relationships.
Classification traditionally focused on defining the relationships among organisms based primarily on their overall similarity in morphology and appearance. Phylogenetics is now the more common approach in studying the relationships among organisms and involves constructing phylogenies, or evolutionary trees, using evidence from evolutionary relationships.
In addition, the advent of genetics and DNA research has significantly changed the way many biologists approach classification, leading in some cases to reconsideration of former taxonomic relationships.
Ancient World and Middle Ages
The roots of taxonomy go back to Greeks, most notably the philosopher Theophrastus in the third century b.c.e., who wrote two treatises on plants, Peri phyton historias (also known as Historia plantarum “Enquiry into Plants,” 1916) and Peri phyton aition (also known as De causis plantarum English translation, 1976-1990). Theophrastus’s system and many other early classification systems grouped plants into herbs, undershrubs, shrubs, and trees.
Classification of plants, beyond this more or less simplistic approach, was not attempted until the latter part of the sixteenth century, when Andrea Cesalpino published De plantis libri (1583). Between the time of the Greeks and Cesalpino, most botanical work was done in the name of medicine, and numerous plants were described because of their usefulness as herbs.
Naming of plants was haphazard, at best. Colloquial names were used by some, and Latin phrases not only were used to describe a plant but also served as official names. There was no accepted length for Latin phrase names, and the names carried little information about how a particular plant might be related to others.
Linnaeus and the Birth of Modern Taxonomy
In 1753 Carolus Linnaeus published his Species plantarum, which quickly brought simplicity and order to the naming of organisms, including plants. Linnaeus introduced binomial nomenclature, which standardized the naming of all organisms by using two Latin words, which together were referred to as the species name. The first word in the species name was the genus, which immediately identified how an organism fit into the classification system.
In addition to improving the system of naming, Linnaeus revolutionized the classification system by introducing a hierarchical approach. Similar species were grouped together into genera. Similar genera were grouped into families. In turn, families were grouped into orders, orders into classes, classes into phyla, and phyla into kingdoms, the most inclusive of the categories.
Although his classification of organisms implied no evolutionary relationships, it was useful for bringing some order to taxonomy. All of these hierarchical categories are used for all types of organisms, including plants, although in plants the name division is sometimes used instead of the phylum.
According to Linnaeus, the turnip, Brassica rapa, which is the name Linnaeus gave to this species, is in the same genus as black mustard, Brassica nigra. The genus Brassica is in the mustard family, Brassicaceae, along with related genera such as Raphanus and Arabis. The family Brassicaceae is in the order Capparales, along with related families like Capparaceae and Resedaceae.
Capparales is a member of the class Eudicotyledones, which includes all the other orders commonly referred to as dicots or dicotyledons. Class Eudicotyledones belongs to the division Anthophyta, along with class Monocotyledones.
Anthophyta, along with all other green plants in divisions like Coniferophyta (the gymnopserms) and Pteridophyta (the ferns), belongs in kingdom Plantae. Each of these categories has a standard suffix, such as -phyta for divisions, -opsida for classes, -ales for orders, and -aceae for families, so that the rank of a name is immediately apparent. Rare exceptions to these rules exist.
In addition to the main categories in the hierarchy, many subdivisions are used. For example, between the levels of kingdom and division, there is subkingdom,which would contain within it one or more divisions.
The sub- prefix can be used before any of the categories, so that there are subclasses, subfamilies, and even subspecies. The prefix super can also be used to define additional ranks. For example, a super family contains one or more related families, and a super order contains one or more related orders.
Classification Since Linnaeus
Linneaus’s binomial nomenclature and hierarchical classification system have been used ever since, but when particular taxa have been added, the classification system has undergone great change. The placement of taxa by Linnaeus was done in what is called an artificial manner.
He grouped taxa into categories based on the organisms’ overall similarities and the possession of particular physical characteristics. Linnaeus’s system is called an artificial classification system because he made no attempt to group taxa based on evolutionary relationships.
Although other plant taxonomists since Linnaeus have also produced artificial classifications, after evolution became more generally accepted in science, many attempts were made to produce a “natural,” or phylogenetically based, classification that would reflect, as much as possible, the evolutionary relationships of the taxa.
One of the first, and still highly respected, phylogenetic classifications of plants was published in 1892 by Adolf Engler. It was actually a revision of an earlier classification by AugustWilhelmEichler. With the help of Karl Prantl and others, the system continued to be elaborated until 1911 and became a twenty-volume work called Die natürlichen Pflanzenfamilien (1887-1911 the natural families of plants).
The families and genera, instead of being ordered alphabetically, were ordered within their taxonomic ranks, from most evolutionarily primitive to most advanced. It was so influential that plant specimens storedinmany herbaria are still organized by what is now referred to as the Engler and Prantl system.
As more and more sophisticated phylogenetic studies have been done, many other plant taxonomists have attempted to improve on Engler and Prantl’s system. Some of themore notable plant taxonomists of the twentieth century have included John Hutchinson, Armen Takhtajan, Arthur Cronquist, Robert F. Thorne, and Rolf M. T. Dahlgren.
The differences among the systems proposed by these various taxonomists aremainly due to different opinions about which plant taxa should be considered most primitive and which most advanced. The identification of what the first land plants, first seed plants, and first flowering plants were like is still uncertain, leaving ample roomfor speculation.
Consequently, a number of competing classification systems exist today. Modern information from DNA analysis and cladistics continues to sharpen taxonomists’ understanding of how plants should be classified, but more work remains to be done.
Naming Rules: The Genus and Below
The rules for naming plants are very specific. The International Code of Botanical Nomenclature (ICBN) contains authoritative rules on the correct way to name plants, as well as groups such as algae and fungi, which have traditionally been considered plants in a broad sense. Rules for naming fossil plants are also covered. Revisions to the code take place on a regular basis.
For a plant name to be accepted, it must be validly published. For any new species (or genus) described before 1953, “validly published” could mean anything from publication in a newspaper or catalog to publication in a respected scientific journal or other professional work.
Since 1953, all new names must be published in accepted scientific publications. In addition, all newspecies (or genus) descriptions must include a complete description in Latin, often called the Latin diagnosis.
Sometimes two or more plant taxonomists inadvertently describe the same species, giving it different names. When this happens, the earliest validly published name is given priority and is considered the correct name any other names are called synonyms.
May 1, 1753, the date Linnaeus published Species plantarum, is considered the starting date for determining priority, and any names published before this date are not considered.
In addition to being validly published, a type specimen must be identified. A type specimen is a preserved plant specimen that is designated by the author as the best representative of the new species.
An author can define more then one type, in which case the first designated specimen is the holotype and duplicates are called isotypes. Each of these is placed in an established herbarium so other plant taxonomists can examine it.
All names of taxonomic groups are treated as Latin, regardless of their source. Proper names and non-Latinwordsmust be Latinized, following specific rules in the ICBN.
Species names always comprise the genus name, with the first letter capitalized, followed by the species epithet, which is not capitalized. Both names must be either italicized or underlined to denote the name as a species name. A complete species name is also followed by the name of the author who named it.
Author names are often abbreviated, and many author names have official abbreviated forms. An example of a species named by Linnaeus is Brassica rapa L. (the L. stands for Linnaeus). The author’s name should not be italicized or underlined.
Once a genus has been referred to in a scientific paper, later references to species within the genus can then be written with the genus abbreviated to just the first letter and the author’s name is left off: for example, Brassica rapa L. becomes B. rapa.
In a species with a lot of variability, subspecies and varieties can also be described. Some plant taxonomists consider subspecies to be of higher taxonomic rank than varieties, whereas others treat them as equivalent.
Often particular taxonomists will use only one of these ranks to describe taxa below the species rank. Any species can be split into two or more varieties or subspecies.
The variety or subspecies that contains the type specimen is always considered the typical variety or subspecies. For example, the species Abies magnifica Andr. Murray (California redfir) has been divided into two varieties. The typical variety is A.magnifica var.magnifica, and the other variety is A. magnifica var. shastensis Lemmon.
Notice that the word “variety” is abbreviated as “var.” and is not italicized or underlined and that the name of the author of the variety follows the variety name (except for the typical variety,where the author is assumed to be the author of the species).
The word “subspecies” is abbreviated as “ssp.” and is also not italicized or underlined. For the sake of simplicity, italics are now often used for taxonomic groups higher than the genus, all the way up to the phylum. However, strictly speaking, only the genus and species names are italicized.
Names can be chosen for a variety of reasons and can be derived fromanything, as long as the source word is Latinized, if it is not already in Latin. One of themost common name choices is one that describers some obvious characteristic of the plant.
For example, the genus name Trilliumnicely describes the fact that essentially all the plant parts are in three’s (tri-meaning “three”), and the species epithet for T. albidumnicely describes the strikingwhite petals of this species.
Names can also be derived from the geographic location where the plant is found. These kinds of names are most commonly found in species epithets, such as Juniperus californica (California juniper) or Carex norvegica (Scandinavian sedge). In rare cases, a genus will be named after a place, as in Idahoa, a mustard genus found in Idaho and elsewhere in the western United States.
Another popular approach is to name a plant after someone famous, as in the genera Darwinia (after Charles Darwin) and Linnaea (after Carolus Linnaeus). Species epithets are often given the name of the person who collected the plant. Examples of this type include Pseudotsuga menziesii and Iris douglasii.
Some species are named with less originality, using very common Latin epithets. For example, Juncus ambiguus, meaning ambiguous, not only is nondescriptive but also leaves some doubt about what the author intended.
Then there is Fritillaria affinis, where the epithet affinis simply means “like.” Like what? In cases like these, itmay be necessary to refer to the original publication where the species is described to understand why the name was given.
Naming Rules: Above the Genus
Above the genus the type concept is used to determine correct names. All family names must be derived from a genus name within the family. For example, the rose family is called Rosaceae, which is derived from the genus Rosa, and the lily family is called Liliaceae, which is derived from the genus Lilium. Exceptions to this rule are only allowed when acted upon by the International Botanical Congress.
In 2001, therewere only eight exceptions to the family naming rules. These are referred to as conserved family names and are of long-standing usage. These conserved names can be used, but each also has a name derived according to the rules, and the names can be used interchangeably.
The eight conserved names, and their alternatives (in parentheses) are Palmae (Arecaceae) Gramineae (Poaceae) Cruciferae (Brassicaceae) Leguminosae (Fabaceae) Guttiferae (Clusiaceae) Umbelliferae (Apiaceae) Labiatae (Lamiaceae) Compositae (Asteraceae).
Two common ranks between the family and genus are subfamily and tribe. Names for these should also follow the type concept, with their name being derived froma genuswithin them. The proper suffixes for subfamilies and tribes are -oideae and -inae, respectively.
Ranks above the family level can be chosen either by the type concept or by using a common characteristic of members of the taxon. Standard suffixes for these higher ranks are mentioned above.
Using the type concept, the flowering plants, or angiosperms, are phylum Magnoliophyta (based on the genus Magnolia), but a common alternative name is Anthophyta. Likewise, the gymnosperms are phylum Pinophyta (after the genus Pinus), but are also commonly called Coniferophyta. In each of these cases, both names are valid and are used preferentially by different plant taxonomists.
Sometimes, not only the names will differ, but even the suffixesmay not followthe standards. For example, using the type concept, the class names for the monocots and dicots (the two major groups of flowering plants) are Liliopsida and Magnoliopsida, respectively. Alternative names, in common use, are Monocotyledones and Eudicotyledones, respectively.
Some common reasons that names change are the result of changes in taxonomic opinion, the discovery that the current name is not the oldest published name, or the discovery that it has some other technical problem.
Although such name changes can be annoying and unpopular to some people, they are essential if the ICBN is to be followed. If plant taxonomists and others were to be free to ignore the rules, then confusion would result.
Plant taxonomists are continually studying relationships among plants, and as new discoveries are made, they are incorporated into the classification system. Sometimes it is discovered that a species needs to be split into two species, in which case the plants that include the holo type retain the original name, and the remaining plants are given a new name.
On the other hand, separate species are sometimes found to be so similar that they are reclassified as belonging to the same species, in which case all the plants from both original species are given the name that was published first. These same rules must be applied to all taxonomic levels whenever taxonomic conclusions warrant splitting or joining of taxa.
Changes in classification at the genus level can also affect species names. For example, if two genera are found to be so similar that they end up being combined into one genus, or some of the species from one genus are found to be more related to members of another genus and are therefor removed into it, species names will be affected.
When this happens, the new species name will carry two authors’ names after it (the original author of the old species name and the author of the new species name), and it is considered a newcombination. The species does not have to be redescribed, but the change must be validly published.
Thus, the species Castilleja exserta (A. A. Heller) Chuang & Heckard used to be in the genus Orthocarpus and was called Orthocarpus exsertus A. A. Heller. Note that the author of the original species name appears in parentheses. Also note, in this case, that the ending of the species epithet had to be changed slightly to follow proper rules of Latin grammar.
Similar rules are followed when a taxon changes from a species to a variety (or some other lower rank) or vice versa. For example, Potentilla breweri S. Watson was later determined to be so closely related to the P. drummondii Lehm. that it was changed to a variety of this species, P. drummondii var. breweri (S. Watson) B. Ertter.
Sometimes a simple study of the published names of taxa in a particular plant group reveals that a currently used name is invalid according to ICBN rules.
For example, it may be discovered that the same species name has been published twice, by different authors who have also identified different holo types. In this case the current name is considered illegitimate and cannot be used, and the name must be changed to the next oldest validly published name.
Alternatively, it may be discovered that a currently used species name is not actually the oldest validly published name, in which case the name must be changed to the older name. Such changes can be controversial, especially when the species is very common and is used by many people who are not plant taxonomists themselves.
Nontaxonomists do not often understand the reasons for such changes. A notable example of this problem is for the species Pseudotsuga menziesii (Mirb.) Franco. The name P. douglasii Carr. was used for many years and led to the use of the common name Douglas fir.
This species is extremely important to foresters, and when the name had to be changed, many resisted the name P. menziesii. With the change in scientific name, the common name should probably be Menzies fir, but it remains Douglas fir.
Future of Plant Taxonomy
Plant taxonomy is a field that has completely embraced modern methods and uses data from molecular genetics, biochemistry, and electron microscopy to gain greater insights into plant evolutionary relationships. The use of computers to perform detailed phylogenetic and cladistic analyses has also revolutionized the field.
A greater emphasis on evolutionary relationships and processes has led to a much better understanding of species concepts and relationships but has led others to consider doing away with the species concept as currently used. Continuing studies using modern approaches should lead to ever better classification systems that better reflect the evolutionary history of plants.
Botanical Taxonomy — A Historical Summary
The names of the plants, whether scientific or common are very ancient.
Many times students have resistance to learning technical names, because
they seem overly artificial, are foreign, or seem devoid of rootedness in
the culture. All of these names came from cultures that we arose from, such
as Gaelic, or Greek. An example is the Hawthorne, Crataegus . This
plant was known and widely used by the Greeks and Romans. The name comes
from the Greek Kratos, meaning strong or powerful, which alludes to the
These scientific names hold considerable power, as well as being a universal
language with which to communicate about particular plants among different
The word taxonomy itself comes from the Greek taxo, to put in order, or
arrange. Humans have had a strong desire to classify everything in the physical
and for that matter astral and ethereal worlds. Rocks, stars, animals, plants,
bacteria all things are given a name, are related to other things of their
kind. This orders the world, and makes sense out of chaos.
Lawrence (2) states: “Early man classified plants before he had a written
language. Certainly he ate plants, or parts of them, used them for shelter,
and from them fashioned weapons for slaughter and defense. For each use,
some sorts were found to be superior and others inferior. Man talked about
these plants. Names for them were a prerequisite to communication., and,
since many kinds of plants were involved, he must have classified them as
well as identified and named them”.
According to Porter (1), “Plant taxonomy has two aims: 1. to identify
all the kinds of plants 2. to arrange the kinds of plants into a scheme
of classification that will show their true relationships”.
The first attempt to classify all the plants known was about 300 BC. by
Theophrastus, the great student of Aristotle. He classified plants by their
habit or form–the trees were grouped together, the shrubs, the undershrubs,
herbs, and so forth. He also recognized more specific botanical characteristics
such as ovary position. His work, History of Plants, is the oldest
botanical work in existence. The system of Theophastus was refined only
a little by other Greek botanists and herbalists. (At this time botanists
and herbalists were one and the same.)
other notables were: Pliny the Elder (23-79 A.D. a Roman naturalist and
scholar who made a notable contribution to early botany, describing nearly
1,000 plants in his 37 volume work, Historia Naturalis.
Dioscorides (first century A.D.) was a military physician under Emperor
Nero of Rome. The Codex, an herbal prepared in 512 A.D. from his
work was still used until the 16th century.
Little botanical progress was made after the decline of the Roman and Greek
civilizations, some of the ancient works being copied and recopied. In the
early 16th century arose a period of intense herbal activity, stimulated
by the reflowering of the arts, especially painting and wood cutting. This
enabled plates of the herbs to be produced. The forerunners of the modern
herbal were produced during this time, notably by the “German Fathers
of Botany”, Brunfels, Bock, Fuchs, and Cordus. The “doctrine of
signatures” was popular during this time. Handed down by the ancient
Greeks, its thesis was mainly relating a shape or color of a plant part
to a part of the body that it was said to cure . Plants with red juice then,
were considered beneficial for disorders of the blood or cardiovascular
system. This feeling persists even today, and in many cultures traditional
herbs are used on this basis. Same of these have been validated by both
traditional medicine and scientific studies for instance the Lungwort,
Lobaria pulmonaria, looks like lung tissue, and also has demulcent
and anti-bacterial properties, and a special affinity for the respiratory
It was not until the 17th century that any taxonamic system of great impact
or importance arose.
A few of the notable contributions include:
Andrea Cesalpino (1519-1603), an Italian physician, used the ancient grouping
into herbs and trees, but recognized the importance of fruit and seed characters.
His writing influenced later botanists, such as Turnefort and Linnaeus.
John Ray (1627-1705), wrote Historia Plantarum, in which appears
one of the first indications of a natural system of classification. He also
used the old groups of herbs and trees, but within these groups he recognized
and named the Dicotyledons and Monocotyledons.
John Ray (1628-1705) was a renowned English naturalist that devised another
system at about the same time. His system was even more refined in some
ways, and he separated the dicots from the monocots.
Pierre Magnol (1638-1715) was a contemporary of John Ray. He found Ray s
system too difficult, and divided plants into families. His name is commemorated
by the Magnolia.
Joseph Pitton Tournefort (1656-1708), a Professor of Botany in France, followed
Theophastus in dividing plant groups into herbs and trees, but greatly refined
the system. He further divided these large, artificial groups into smaller
ones based on the flowers being petal or non-petal bearing, regular or irregular,
etc. He was the first to group plants by Genera (a distinction usually attributed
to Linnaeus) as we know them today. Genera are natural groups under family,
i.e., the Oaks, Roses, Maples.
Carolus Linnaeus is probably the single most dominant figure in systematic
classification. He had a mind that was orderly to the extreme. People sent
him plants from all over the world, and he would devise a way to relate
them. At the age of thirty-two he was the author of fourteen botanical works.
His two most famous were Genera Plantarum, developinq an art:ificial
sexual system, and Species Plantarum, a famous work where
he named and classified every plant known to him, and for the first timel
gave each plant a binomial. The binomial consists of a Generic name
(Rosa, for the Rose), and a specific epithet (rugosa) for a particular Rose.
This binamial system was a vast improvement over same of the old descriptive
names for plants used formerlv. Before Linnaeus, Catnip was known as: “ Nepeta
floribus interrupte spicatis pedunculatis “. which is a brief description
of the plant. Linnaeus named it Nepeta cataria –cataria meaning “pertaining
to cats”. The binomial nomenclature is not only more precise and standardized,
it also relates plants together, thus addinq much interest and information
in the name. For instance, Solanum relates the potato, the tomato and the
Species Plantarum was the starting point for the svstem of binomial
priority used in our present-day system of nomenclature. From that point,
there were many botanists that contributed to the evolution of taxonomy.
Antoine Laurent de Jussieu (1748-1836) created many of the familv groups
that we use today, and created a much more natural system than ever before.
Sir Joseph Hooker (1817-1911) contributed an outstanding svstem of classification
in his Genera Plantarum, which described around 202 orders (now families),
qrouped into cohorts (now orders). He was associated with the Royal Gardens
at Kew in England.
Asa Gray (1810-1888) is the father of American Botany, and wrote several
important botany texts and floras, which can still be found in used book
stores today, and are useful for their clear explanation of plant morphology.
August Wilhelm Eichler (1839-1887), Adolf Engler (1844-1930), and Charles
Bessey (1845-1915) helped refine previous schemes to make the system we
have used until the last few Years, when even further refined, using modern
research methods and equipment, such as chemotaxonomy and electron microscopy,
by Dr. Armen Takhtajan, and Dr. Arthur Cronquist. These systems are similar,
and are in current use in botany texts of the last few years.