A few weeks ago I was doing a little research on a glorious plant well known to all, the dandelion. As always, when I write a text for this blog or when I prepare material for teaching, I validate the Latin names on Plants of the World Online or on Canadensys (for native and introduced vascular plants of Canada). I know the Latin name of the dandelion, Taraxacum officinale: this verification was supposed to be only a formality. I’m already eager to move on with the rest of my work when Oh! Surprise! My dandelion is not there!
Finders Keepers… well, Almost!
The computer tells me that Taraxacum officinale does not exist! What? It suggests another name. That’s when I pull out my detective’s magnifying glass to unravel the mystery: what happened to my dandelion?
First described (well, we’ll see about that later) in 1780 by German botanist Friedrich Heinrich Wiggers, the dandelion has been known and used for millennia. It’s already known to be widespread throughout Eurasia. It’s in his fabulous book Primitiae florae Holsaticae (Primitive Flora of Holstein, Holstein being a region of northern Germany) that Wiggers describes the plant in botanical terms, in Latin, of course! The Taraxacum officinale was born! According to the conventions of the Code of Botanical Nomenclature, the first to describe a plant in Latin is the proud holder of the “trademark” and therefore holder of the Latin name that will be used to name the plant, everywhere in the world. That’s something! Wiggers had just won the honor of naming one of the most universal plants on the planet: our good old dandelion, Taraxacum officinale!
But Oh! Scandal in the house! Our dear Linnaeus, father of the binomial nomenclature, had already described this plant… under the name of Leontodon taraxacum! Yes, it figures in the second volume of the Species Plantarum, published in 1753. So… logically, the real Latin name for dandelion should be Leontodon taraxacum.
Two hundred years later…
How can we explain this major fault? (We’re having fun here. It’s not that dramatic, actually) Like an elephant in the room, the subject has been avoided for over 250 years! Wiggers won over Linnaeus! And no one objected! Perhaps is it because the genus Taraxacum has become very important with its 2,458 recognized species. Yes, you read correctly! Our dandelion is not unique! It has many, many cousins spread all over the world! The entire northern hemisphere is covered in dandelions of all kinds. It seems absent only in desert regions. And I can confirm to you that it grows at more than 13,000 feet of altitude, to have crossed it there. In fact, Canada has 14 recognized species of the genus Taraxacum.
A Matter of Bracts
It may also be because other specimens of the genus Leontodon are quite different in appearance from dandelions. The flower stalks are thinner and longer. This can be seen clearly with the naked eye, even if you are not an expert!
Could Linnaeus be wrong? How to circumvent the rules of the Botanical Nomenclature Code? In 1985, we dared and we decided: our domestic dandelion looks much more like an actual dandelion (Taraxacum spp.) than a hawkbit (Leontodon spp.). What a relief!
In fact, these two genera are distinguished by the observation of the bracts under the flowers. Bracts are small scales that originally form the flower bud. When the flower is in full bloom, they can be observed under it. In dandelions (Taraxacum spp.), there appear to be two rows of bracts, one curved downward and the other erect. Hawkbits (Leontodon spp.), also called fall dandelions, have only erect, slightly overlapping bracts.
The Dandelion… More Complex Than you Think
Unfortunately, it was too early to say “Mystery solved!” The incredible diversity of dandelions has given numerous headaches to many of the world’s leading experts on the genus Taraxacum. Here the bracts are like this, there the plant is polyploid. That’s without mentioning the genetics and mode of reproduction of dandelions (I’ll spare you the part on apomixis and microspecies). The only conclusion on which botanists agree is that the common dandelion, as gardeners around the world know them, is not a single dandelion. There are hundreds, if not thousands of different species!
Faced with the insoluble ambiguity of this plant, which is nevertheless so common, our dear scientists have proposed to create an infraspecific category, a section, grouping together the different forms and origins of our dandelion… and abandoning the officinale epithet. Then, they devoted themselves body and soul to find the perfect name for this new group: Crocea, Ruderalia, Vulgaria … nothing suited perfectly. And that’s how they arrived at a result. The correct name (for now) would therefore be Taraxacum sect. Taraxacum.
Rest assured, our precious botanists know well that their entertaining name changes exacerbate gardeners and horticulturists. And on that subject, we gardeners are protected by the Code! Because it ways “that it is necessary to avoid changes of names which could create errors or plunge science into confusion”. Thus, the non-scientific community can continue to use Taraxacum officinale and that’s fine! Till then, I will keep my popcorn handy and wait for the next round of botanical nomenclature arm wrestling!
