When Carl Linnaeus developed the binomial system of nomenclature for plants and animals in 1753, where each species was placed in a genus (the first name) with other closely related species, then given a specific name (the second name) that only applied to it, it was designed to simplify their naming. So, you’d have species with names like Homo (genus) sapiens (species) for humans or Taraxacum officinale for the dandelion and the same name would be applied all over the world. No more biological tower of Babel!
The system has worked fairly well over the last 250 years, although, for various reasons, some names have been changed … but never so many as today. That’s because taxonomists (scientists who name plants) have a new tool not available in Linnaeus’s time: in-depth genetic studies. He grouped species together according to the appearance of their organs, notably those of their sexual parts, and that was usually pretty accurate.
Evolution can lead two beings to evolve similar organs even though they’re not closely related. And the newly acquired ability of being able to study the DNA of plants and animals (DNA sequencing) means we can look more deeply into the makeup of any being than was ever possible in the past. This has revolutionized the field of taxonomy and caused a great deal of change in scientific names as the true relationships between species are slowly revealed.
Putting a Name on It
The result of this is that many well-known plants (I’ll stick to botany here) have changed names … often repeatedly, as more is learned about them. The coleus went from being called Coleus blumei to Solenostemon scutellarioides and is now Plectranthus scutellarioides. The Monterey cypress went from being Callitropsis macrocarpa to Cupressus macrocarpa, then Neocupressus macrocarpa, then back to Cupressus macrocarpa … and now it’s possible it will end up with yet another name, to Hesperocyparis macrocarpa.
(I wrote in more detail about this in Why Do Plant Names Change? and you might want to read that.)
The question now becomes: what is the current accepted Latin name of any given plant? People like myself, who share knowledge about plants—writers, lecturers, teachers, bloggers, gardeners, etc.—, need to be able to put the right name on the right plant. But where do you go to find it?
For the last few years, I’ve been using The Plant List, subtitled A working list of all plant species, as my source of up-to-date botanical names. It provides the accepted Latin name for most species. Over one million species names, 350,000 considered valid, appear on it in about 17,000 plant genera. The two principal collaborators are the Royal Botanic Gardens, Kew, and the Missouri Botanical Garden, two places I used to go for confirmation of plant names anyway.
When I have a plant whose botanical name is in doubt, I go to www.theplantlist.org, enter the botanical name I know, and the screen then shows me the current status of the plant’s name. There’ll be an Accepted name and, most likely, a series of synonyms, names it once had. I use the Accepted name in my writing and lecturing.
Of course, The Plant List isn’t perfect. First, some 20% of plant names are listed as “unresolved,” meaning more work is needed in determining the correct name (fortunately, most “unresolved” names are of rarely grown plants). Also, it will never be 100% up-to-date, as it is only updated periodically. For example, I know from other sources that the botanical name of Monterey cypress (mentioned above) is likely to change from the current Accepted Latin name of Cupressus macrocarpus to Hesperocyparis macrocarpa, but I’ll stick to the Plant List name until it officially recognizes the change.
You’ll find that many, perhaps most, people working in the field of horticulture do the same.
Not sure of a plant name? Just go to The Plant List. It will give you a good enough name for your purposes!