There aren't as many plants as we thought

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It is well known that the same organism may be known by different common names in different areas (e.g. "cougar", "panther", "puma", and "mountain lion") and that the same common name may be used for different organisms in different areas (e.g. "blackberry"), but the assumption is that (pseudo-)Latin scientific names like Achillea millefolium "yarrow" are unique. Recent work by Kew Gardens and the Missouri Botanical Garden, with numerous collaborators, has revealed that this is not quite true: of 1.04 million species-level names, they classified only about 300,00 (29%) as accepted names. They classified 480,000 names (46%) as synonyms for accepted names and 260,000 (25%) as unresolved, meaning that the available data is not sufficient to determine whether or not they designate distinct species. By way of example, a query for Achillea millefolium reveals that it has synonyms such as Achillea ambigua, Achillea angustissima, Achillea borealis, and even some in other genera, such as Chamaemelum tanacetifolium. You can look things up yourself at The Plant List.

No word yet on beetles.


  1. Robert Coren said,

    December 31, 2010 @ 5:44 pm

    Please tell me that you chose this particular example because of the felicity of Achillea ambigua in this context.

  2. Bill Poser said,

    December 31, 2010 @ 6:51 pm

    Well, I can only claim partial credit. I used Achillea millefolium as a trial search term simply because it was the first name that came to mind. However, once I saw that Achillea ambigua was a synonym, I did recognize the felicity of the example .

  3. Jonathan Badger said,

    December 31, 2010 @ 7:38 pm

    I don't know who assumes scientific names are unique. A major issue in systematics ever since Linnaeus is determining priority of names. Sometimes this even makes it down to the general public, as the whole Apatosaurus/Brontosaurus controversy,

  4. Bill Poser said,

    December 31, 2010 @ 7:54 pm

    I think that non-biologists do tend to think that scientific names are unique. That's what is taught in, e.g., biology classes, and most people simply don't encounter the disputes that arise among naturalists and systematists. Examples like the Apatosaurus/Brontosaurus controversy only rarely come to the attention of the general public.

    Another issue is the extent of duplication. I was aware that from time to time the same species is named more than once, but was surprised at the number of synonyms for Achillea millefolium, a rather common species. I had been under the impression that the typical situation was that there were just a couple of names, perhaps because a later scientist had not been aware of some earlier description, or because it had not been recognized that widely separated varieties were the same species. In spite of my awareness of the phenomenon, I was surprised both at the number of synonyms there are for some organisms and at the percentage of species for which there is more than one name.

  5. John Cowan said,

    December 31, 2010 @ 7:55 pm

    No news here. Mergers are common things in taxonomy as in historical phonology, and when one occurs, one of the names becomes a junior synonym. Thus it is not true that Brontosaurus was changed to Apatosaurus, merely that the two were recognized as synonymous, and since it so happened that Apatosaurus had been assigned first, it became the preferred name. Brontosaurus remains a perfectly legitimate name for the genus, though not to be used in future scientific papers.

    Per contra, although the name Manospondylus, referring to a different genus of dinosaurs, was published in 1892, it was never used very much. It was in effect superseded by the very well known name Tyrannosaurus, though that was not published until twenty years later. Consequently, Tyrannosaurus has been made by a special ruling of the International Commission on Zoological Nomenclature the preferred name.

  6. Bill Poser said,

    December 31, 2010 @ 8:02 pm

    One further point: the assumption of uniqueness that I mentioned is really two assumptions, an empirical assumption, that systemacists have got everything sorted out and eliminated duplicate names, and a prescriptive assumption, that there should be a unique name for each organism.

  7. Bill Poser said,

    December 31, 2010 @ 8:07 pm

    Jonathan Badger@With regard to what the average person knows about biology please consider the fact that according to the latest Gallup poll, 40% of Americans believe that human beings were created by a divine being within the last 10,000 years. Ignorance is vast.

  8. John Atkinson said,

    December 31, 2010 @ 9:19 pm

    On the opposite tack: Since the advent of comparatively cheap gene analysis, more and more phenotypically similar geographic varieties of a single putative species are being found to be two or more separate species genetically, and given different names. So there are more plants than we thought as well.

    It's not clear, to me anyway, .which of these two opposing phenomena is winning out.

  9. Peter Taylor said,

    December 31, 2010 @ 9:31 pm

    You could have used panther as an example for "the same common name may be used for different organisms", too. It seems to be used for three different big cats.

  10. Faith said,

    December 31, 2010 @ 10:29 pm

    I am still reeling from the news that puma, panther, cougar and mountain lion are all the same animal.

  11. John Cowan said,

    January 1, 2011 @ 1:14 am

    Faith: The names cougar, mountain lion, and puma are all unambiguously Felis concolor. However, panther is an ambiguous common name: in North America, it is the cougar; in South America, the jaguar (Panthera onca); in Europe and Asia, the leopard (Panthera pardis), most often applied to all-black individuals.

  12. Garrett Wollman said,

    January 1, 2011 @ 1:38 am

    @John Cowan: You can add "catamount" to that list of vernacular names. (Speaking as someone who grew up in Vermont but will always remain a flatlander.)

  13. Leonardo Boiko said,

    January 1, 2011 @ 4:37 am

    As a single data point, until recently I did assume (without giving the question much thought) that scientific names were an one-to-one mapping. Just the other day I was suggesting the Japanese word 弟切草 オトギリソウ otogirisou, St. John’s Wort, to a collaborative dictionary. Then I noticed the dictionary already had オトギリソウ科, the “otogirisou family”, as Clusiaceae. But the wikipedia page for the herb said the family was Guttiferae. A closer look revealed these to be alternative and valid names for the same family.

    My faith in the infallibility of botanists was shaken!

    In any case, even if you were well aware of synonyms and disputes, aren’t the numbers found by this study still surprising?

  14. Chris said,

    January 1, 2011 @ 10:48 am

    Surprising? Not to anyone with biology training.

    I'm actually surprised that anyone would think that counting scientific names would be a reasonable way of counting species.

    Synonyms arise in many ways — for instance, two people may unknowingly describe the same species, in which case the earlier name usually takes precedence. This has happened especially often with dinosaurs, where skeletons are often fragmentary — one person may describe something from evidence of leg bones and the spine, another from a skull, and later it is realized they are the same animal.

    Also, some taxonomists are "splitters" and describe every variant as a new species, while others are "lumpers" and believe that there are fewer species with more variability.This is why in formal scientific literature the Latin binomial is often cited with its author (or an abbreviation of the name of a well-known author) appended at the end: for instance, Taraxacum californicum Munz & I.M. Johnst., an endangered California species of dandelion. This clarifies, should it be necessary, that it is Munz and Johnston's version of the species description that's under discussion here.

    BTW, Wikipedia under "cougar" notes that a 1993 paper proposed that Felis concolor should instead be placed in the genus Pantheris, on the theory that pumas are more closely related to the southern jaguarundi than either of them is to domestic cats. I don't know how widely accepted that has been. ;)

  15. Chris said,

    January 1, 2011 @ 10:57 am

    P.S. Clusiaceae versus Guttiferae is, IIRC, one of the rare cases where there actually are two valid names for the same thing — in this case, a plant family. Ordinarily, there is an international committee on nomenclature that will rule on which of the different names for something is the valid one.

    Certain plant families were originally named from some common characteristic of the plants in them — for instance, Umbelliferae (for the upside-down umbrella shape of many species' flower clusters), Guttiferae (for the distinctive resin glands on many species)and the Compositae (floral heads composed of many small flowers, such as daisies and dandelions). More recently, family terminology has been brought into line with the pattern used for naming subfamilies, orders and so forth, so that every family is now named for a "typical" member: Umbelliferae is now Apiaceae (after the genus Apium), Gramineae (the grasses) is now Poaceae (after the genus Poa) and Compositae is now Asteraceae (after the genus Aster).

  16. Nadia T. said,

    January 1, 2011 @ 11:18 am

    As John Atkinson noted above, a lot of splitting is currently occurring, and the recent predominance of lumping seems to be on the wane. Old names are being resurrected for sub-parts of groups, for example, the Bornean clouded leopard Neofelis diardi, "discovered by DNA barcoding in 2006", was described by Cuvier in 1823.
    About the Clusiaceae/Guttiferae example, that came about through standardization of botanical family names: now they must end in -aceae, except for seven that were so well known that it was considered disruptive to insist on change, and Guttiferae is one of those. Seven with duplicate names out of approximately 462 families isn't bad. The bigger issue is that species get moved between genera, usually because of additional information, and a new name is needed with each move.
    As an aside: the Plant List is far from complete or polished, but that is another (fraught) discussion.

  17. ~flow said,

    January 1, 2011 @ 2:43 pm

    i once worked as a programmer at the botanic(al) garden (they preferred one of the two possible forms, but i could never memorize which one) here in berlin, during which time i became aware of the immense complexities in both plant taxonomy and the modeling of that knowledge into relational databases. the database schemas had almost the size of a small billboard, and filling data into those schemas was always fraught with uncertainties, difficulties, and compromises. i have come to work with very, very simple database schemas for my taxonomy of chinese characters and am very thankful for the valuable teachings. the problem is basically that you have to have a very concrete idea of the structure of your subject before you can cast that into an RDBMS schema; this knowledge, however, can only come from working intensively with the data, so its a cat & tail problem.

    it was very sobering to see how much taxonomists realize that botanical classifications are but an idea where the naive bystander treats them as realities. few people know that botanists often travel continents to visit a particular collection which holds or may hold the decisive scientific first find, and then they sit for weeks to compare specimens.

    at this point i always recommend reading up on ring species on wikipedia; it is easy to memorize and whenever the discussion comes up in the bar or at the dinner table, you can let a few seagulls out of your hat that demonstrate a vexing and educational taxonomic problem.

  18. Bill Poser said,

    January 1, 2011 @ 7:01 pm

    The thing that really bugs me about cougars etc. is that I have never seen one in the wild. I've seen lots of animals in the wild, even a wolverine, but never a cougar, and that in spite of having visited quite a few times what is reputedly the best cougar habitat in the world (Sally Thomason's part of Montana), which is indeed crawling with deer.

  19. Bill Poser said,

    January 1, 2011 @ 7:03 pm

    As a linguistic side note, something that did not, I think, affect real biologists is the use by some amateurs, such as Father Adrien-Gabriel Morice, to whom we owe all the serious early documentation for Carrier, of the scientific names of European species for North American species that were not in fact the same species. Morice, and I am told, others, seem to have equated European and North American species too readily.

  20. Bread and Roses said,

    January 1, 2011 @ 8:25 pm

    Bill Poser: me too. I think the cougars like it that way.

    My sister's horse was attacked by a cougar, at night, on an overnight trail ride when I was in 3rd grade, but not only did I not get to see the cougar (one of the adults did), I slept through the whole incident, including being lifted up in my sleeping bag and brought closer to the campfire. That was probably my best chance ever to see one.

    I find common names to be just as useful for disambiguation of scientific names as scientific names are for common names.

  21. chris said,

    January 3, 2011 @ 9:57 am

    Genera, families, and all the higher classifications don't really exist — they're a structure we impose on lifeforms for our own convenience. Species are arguably less artificial for *some* (but not all) living organisms, but when you include dead ones then every pair of species is connected by a (very long) web of ancestors and descendants, each of which is as similar as any parent and child. Where to draw the species lines, let alone the higher-order-classification lines, on that web is pretty much a matter of choice, not an objective reality that can be discovered.

    So it's not surprising to me that the nomenclature gets confused: it's an attempt to impose disjoint categories on a (near) continuum of actual lifeforms.

  22. David Conrad said,

    January 4, 2011 @ 9:04 am

    Erratum: for 300,00 read 300,000.

  23. John Cowan said,

    January 4, 2011 @ 6:24 pm

    Chris: If we had perfect information about every parent-child relationship, we would be able to segment the tree into groups where there is ancestral convergence only within a group, and that would be a perfect notion of species. (Ancestral convergence means that since you have 2^n ancestors of degree n, you quickly come to the point where you have more ancestors than members of the species that existed at the time.)

  24. Greg Morrow said,

    January 6, 2011 @ 2:50 pm

    Bill: It is my understanding that the reason Felis concolor is not at all endangered is that it was fortunate as a species in having both the ability to hide from us and the preference to hide from us.

  25. Georgia Picton said,

    January 24, 2014 @ 12:46 am

    I was aware that from time to time the same species is named more than once, but was surprised at the number of synonyms for Achillea millefolium, a rather common species.

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