Fine cooking out in the cabbage patch

In the most recent issue of the fine cooking magazine Fine Cooking, the writers have gone out on a somewhat thin taxonomic limb.

The Brassicas article in Fine Cooking.  Photo by BotanicalAccuracy.com.

So, what do they write?

"Arugula and turnips bear little resemblance to one another on the plate, so you might be surprised to learn that they both belong to the cabbage family, otherwise known as Brassica."

Well, arugula and turnips are both member of the cabbage family, but that family is called Brassicaceae, the mustard or cabbage family. Even if turnips is placed in Brassica, arugula is not, and in fact, the two commonly cultivated species of arugula are in different genera.

The article continues:

"Other members include broccoli, Broccolini, broccoli raab, Brussels sprouts, cauliflower, cabbage, collard greens, mizuna, tatsoi, kale, watercress, radish, and horseradish." 

Yes, these are all members of the mustard family Brassicaceae, but not all are species of the Brassica genus. Brassica is one of about 375 genera in the mustard family.  Some of the species listed are actually cultivars (domesticated varieties) of the same species of Brassica.  And what is going on with that capitalization on common names?  Lets capitalize every second word that starts with B?   

So how does this all work?  What is really the same genus and species of these delicious plants?  There are many cultivated plants in the Brassicaceae family (the mustard family). Brassica gave its name to the family Brassicaceae, like Rosa (roses) to Rosaceae (rose family), and Poa (bluegrass) to Poaceae (grasses). All plant families have scientific names that end with '-aceae', rather convenient when you try to tell them apart from other group names.

Giant cabbages (Brassica oleracea) at a market in Uzbekistan. Photo by Lena Struwe (Creative Commons).

There are many, many species and cultivars of Brassica (or brassicas, as they are sometimes called in English). The cultivated brassicas are ancient and a result of a lot of breeding, selection, and crossing of genotypes, so their taxonomy is a bit messy within Brassica itself. Sorting out the current common names, their scientific names, and classification of the brassicas has to wait for another blog post (which is in the works). But, the summary is:

The Brassica genus is a member of the family Brassicaceae. Many other edible mustard plants are placed in other genera of the Brassicaceae. 

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

Lessonia: 'Marine lichen' is not a lichen, it is a red algae

Lessonia is a company that provides ingredients to cosmetics companies.  They specialize in exfoliators and botanical extracts, including several from seaweeds. 

So, what is a seaweed?  This common name has been used for all multi-cellular (= not one-celled planktonic) algae that grow (mostly) in marine areas, regardless of which group of algae they belong to.  So included in seaweeds are green, red, or brown algae, which all belongs to different evolutionary lineages. You have kelp (brown), sea lettuce (green), carrageenan (red), nori (red algae of sushi fame), and so on.

There are only a few flowering plants that live in the ocean similar to seaweeds, the most well-known being eelgrass (Zostera marina).   So, seaweed is a practical common-name term we humans use and it groups many unrelated plants together. Algae is the same, that group name is also a practical group name of no taxonomic use anymore since it doesn't define an evolutionary group with a common ancestor and common history.

The group 'Algae' in fact includes members from maybe 8-9 different evolutionary lineages.  We taxonomists sometimes call such groups 'taxonomic trashbags', since they contain a mishmash of many different things that are unrelated to each other.  But when you talk about oceans, we can use the term algae just to identify their plant life.

Irish moss (Chondrus crispus), a red algae.
(cc) Vilseskogen on Flickr

Back to Lessonia - this company sells something call Lichen Glycerin Extract.  In their brochure about this product, also called 'Marine Lichen', they say:

"Marine lichen lives on rocks, in pools, lower intertide."

"The Lichen glycerin extract is [...]  polysaccharides contained in this red algae.  "

The listed ingredient for the Lichen Glycerine extract following the INCI guidelines are:

"GLYCERIN & WATER & CHONDRUS CRISPUS EXTRACT"

Irish moss (Chondrus crispus).
Public domain image, Chondrus, Wikipedia

So, what is Chondrus crispus?  This species of red algae is often called Irish moss or carageen moss, and is the marine source of the compound carageenan, a thickener often used in icecream and many other food products (and some cosmetics too).  This plant has absolutely nothing to do with lichens, and in fact, there are no lichens that live in the sea.  On the rocks along the shore, yes, but nothing permanently under water.  To call this 'Marine Lichen' is as wrong as calling an elephant a giant ostrich.  

Why not call this MARINE IRISH MOSS EXTRACT?  

This plant has already the common name of 'Irish moss', which of course has nothing to do with real mosses that are green land plants - but traditionally commonly used names are OK to use.  Introducing a big misrepresentation by calling this plant a lichen is something very different. Lichens, by the way, are organisms where a fungus and a plant (usually green algae) live together in symbiosis.  Which is very cool!