Botanical Accuracy: August 2014

Tuesday, August 12, 2014

Coleus - I am calling your name! (But what is it?)

Many gardeners and naturalists are frustrated when we botanists change the scientific names of species. I feel frustrated too, when the crown vetch changes its gorgeous, easy-to-remember (for me) name Coronilla varia, to Securigera varia. Now the genus name sounds like a financial security company, not like a gorgeous crown of pink flowers.

But change happen, and it happens for a good reason. We are sorting out old problems and making things better and more logical in the long run. Keep on reading and you will find out what

Coleus hybrids.
(cc) photo by Pharaoh Hound on Wikimedia.

Wild species change genus for mainly one reason. We try to classify all species with their closest relatives, so that everything in a genus comes from one common ancestor species. That means, all species has one origin back in time and share a common history. To figure out this history and these relationships we use DNA and morphology, and build up evolutionary trees that shows the story of species evolution over time.

Of course, when most plants were first described, they weren't part of evolutionary studies. We first started to construct evolutionary trees using DNA and computers in the late 1980s. In the beginning of botanical taxonomy at Linnaeus' time we didn't even know about evolutionary theory, since that came about in the 1860s with Darwin. The start date for botanical nomenclature is Linnaeus book Species Plantarum from 1753. Before recent times, scientists gave species their scientific placement and names based on overall similarity or dissimilarity, not evolutionary relationships.

In the blogpost about "Magilla Perilla" we listed the scientific name for coleus as Solenostemon scutellarioides. We also listed two older synonyms as Plectranthus scutellarioides and Coleus blumei. A few weeks ago we e-mailed botanist Alan Paton, who works on the evolution of this plant group at Royal Botanic Gardens, Kew in London, and asked him, "What is the correct species name for coleus, for real, and where does it belong?"

His answer was maybe not what you expect. He said:

"I'm writing up the research at the moment. [...] Plectranthus including some other genera on one hand and Coleus and some other relations including Solenostemon form sister clades. The actual picture with denser sampling shows a slightly more complex picture than these earlier papers; but they give an outline which suggests Coleus should be recognized and Solenostemon would be embedded within it."

What does this mean? Be prepared to see the scientific name your garden coleus change back to original genus Coleus in the near future, and Solenostemon will be no more (it will be merged into Coleus). Plectranthus will still be around but with fewer species and not include your garden coleus. So, coleus will be a Coleus again, which is very nice, and certainly easy to remember. It has been a mess with these names, but Alan is sorting it all out, once and for all. Check back here on the Botanical Accuracy blog when his paper comes out for an update.

It is really all about getting the right species in the right place in the giant evolutionary family tree, which includes over 300 000 plant species in the world. No wonder it is a little chaotic at times. But we have to do it, and we have to use the most updated scientific names possible to talk to each other about plants and understand our plants, across over the world. It is all part of the progress of knowledge. And sometimes increased knowledge isn't that convenient to begin with.

References:

Paton, A. J., et al. Phylogeny and evolution of basils and allies (Ocimeae, Labiatae) based on three plastid DNA regions. 2004. Molecular Phylogenetics and Evolution 31: 277-299.

Lukhoba, C. W., M. SJ Simmonds, & A.J. Paton. 2006. Plectranthus: A review of ethnobotanical uses. Journal of Ethnopharmacology 103: 1-24.

'What is in a (PLANT) name?' on the FLORIDATA website

Update on the magics of "Magilla Perilla"

Art Tucker and I have been getting a few e-mails about the blogpost explaining that Magilla Perilla is just a cultivar of the regular Coleus. We thought we should clarify a few things for those of you that wonder and ponder the naming of plants.

Just because a name is listed in large, well-known databases run by organizations such as Royal Horticultural Society, doesn't mean the name is correct and accurate. Many times common mistakes have been perpetuated throughout the online or printed publishing world. Often new facts have come to our attention, but the name has not yet been corrected by most sources. In printed books the mistake will live on until a new edition comes out.
Magilla Perilla is a coleus. That has been shown by looking at scientific evidence such as anther morphology and annual versus perennial habitat. (See more information in this newsletter.)
Magilla Perilla is not a member of the Perilla genus. If you are not convinced, grow some Perilla, some coleus, and then some 'Magilla Perilla'. Do your own scientific studies and compare. Hands-on science in the garden or backyard is a great thing.
What is the scientific genus name of coleus? Well, that has now turned into a separate issue, and justifies its own blogpost, which will follow this one.

Diagram showing where "Magilla Perilla" belongs = with the coleus, not the Perilla.
Copyright by BotanicalAccuracy.com

What is Botanical Accuracy?

Would you care if someone called a cat 'a mouse' in the description of a medieval painting?

Would you care if someone served you horse meat, but said it was beef? I bet you would.

Would you care if the wrong chemical was listed in the ingredient list of your shampoo or cereal?

Would you care if you bought one plant, but got another?

Would you care if there were species or ingredient mistakes in advertising, menus, herbal pills, and such things?

Would you care if books on plants are illustrated with the wrong plants?

If so, here is the place for you to read about such problems in the world of plants and plant products, where unfortunately such mistakes, inaccuracies, and problems are not uncommon. This is usually due to lack of botanical knowledge or expertise, or sometimes because of plain ignorance.

Inaccuracies are common when it comes to plants, because it seems like we humans care to learn less about green things like trees, flowers, and herbs than we care to learn about animals, even when we eat plants, paint them, plant them, extract their chemicals, or use them in numerous other ways.

Without plants in the world you and I certainly would be dead. Some plants can also kill you with their toxins, so it is best to know which plant is what species. Time to learn some botany!

About mistakes, inaccuracies, and errors

Science is a process of gaining knowledge and understanding of the world around us. It is a never-ending process, and what we think are true facts today might change tomorrow. In science we are aiming for having the best understanding possible today based on what we and our predecessors have learned until now.

This means that what is botanically accurate from a scientific viewpoint might (and will) change. Other experts in the field of botany know a lot more about their particular research plants than I do. New scientific findings and conclusions are being published every day. This is just normal and part of the scientific process; we improve on our knowledge all the time.

The important thing is our willingness to continuously aim for botanical accuracy and the highest scientific standards in our use of names and facts. When things are wrong, let's correct them. Let us not perpetuate wrong botanical knowledge by accepting its incorrect use on commercial products, in everyday language, or in other parts of our contemporary cultures. Through scientific education and specific corrections we will improve botany and science for everybody, in supermarkets, restaurants, and garden centers.

It is the perpetuation of incorrect facts that are the problem, not the need for correction. Everybody makes mistakes, and everybody learns, throughout their lives. We need words to be able to communicate and talk about things, so let's use the right words and the right species names.

Undoubtedly there will be mistakes and errors on this blog, or things that need to be updated. If you want to get in touch, please e-mail me at botanicalaccuracy at gmail.com. If you see a mistake on this blog, e-mail me with the link to the post and an explanation what is incorrect and should be updated. If you represent a company and want to get in touch, please use the same e-mail address.