What’s in a name
What’s in a name?
Common tree names have long since been bugging me. For instance, the name Mountain Ash, in North America it’s known as a Sorbus americana a small sub canopy tree. The Australians call a Mountain Ash something entirely unrelated: Eucalyptus regnans. Its namesake is not a small sub canopy tree, it’s only the tallest flowering tree known worldwide reaching heights of over 100 meters! Oh, and might I add: Neither of these are related to the ash family (Fraxinus).
Sycamore, don’t get me started… Here in New Zealand, we know it as a locally invasive species Acer pseudoplatanus. Its species name literally means ‘false plane’, what the North Americans call a Sycamore is exactly that, their Plane tree: Platanus occidentalis. One is in fact a maple, the other a plane tree, it’s just that someone at some stage decided it looked somewhat like a Sycamore as described in the bible; Ficus sycomorus that has a wide heart shape leaf. I once saw a Ficus sycomorus in the Brisbane Botanic Gardens and based on that I find it a bit far-fetched, but that’s just opinion. Probably an English person went to the holy land and started calling Acer pseudoplatanus a Sycamore. Subsequently, when English settlers moved to North America and encountered a Plane tree decided it has some resemblance to what they know from home and hence the name stuck.
When first settlers arrived in New Zealand, they also gave names to trees that somewhat resembled from what they knew from back home, for instance the name White Pine was given to Kahikatea (Dacrycarpus dacrydioides) and Brown Pine to Miro (Prumnopitys ferruginea). Fortunately, we have all but forgotten about these names and call them by their Māori name. One common name has stuck though, and I cannot think of a more generic name for a particular tree; Broadleaf (Griselinea littoralis)! I find its Māori name Kapuka by far more graceful.
Common names, how confusing!
Enter this guy:
Bronze statue of Carl Linnaeus in front of his family home, Uppsala. Photo: Menno Kluiters
It is Carl Linnaeus (1707-1778) we have to thank for the classification system we use. This system, otherwise known as binominal nomenclature, categorises related species under a genus name followed by the species name. Like I already used extensively above! Sure, Linnaeus was not the first to give Latin names to Flora and Fauna but it was him that devised the system that we know today. He first presented this system in his work Systema naturae when he was only 28 years old.
Pre-Covid I was fortunately enough to do some work in Sweden, and one weekend I took the opportunity to visit the Linnaeus Museum in Uppsala. This was the original botanical garden that was established before Linnaeus’s appointment there as a professor in 1741, he took up residence in a house onsite. Here he expanded the collection of plants and these were arranged according to his new classification system. At the garden he received students as he was a particularly popular teacher, reportedly much to the annoyance of his colleagues. Perhaps somewhat like Indiana Jones? His improvements made it one of the world’s foremost gardens. Today his house is a museum, with personal belongings and scientific artefacts. The garden is restored as how it would be in Linnaeus’s time, and only species known to have been cultivated in that time period are allowed. Most plants are arranged in neat rows with small white signs, that give it a unique atmosphere, unlike any other botanic garden that I have visited.
The Linnaeus garden today. Photo: Menno Kluiters
Humans appear to have the need to organise their surroundings in systems to understand them, I for one, am one of those. Carl Linnaeus’s system was originally based on how the sexual system of a plant is arranged, loosely in how many stamens a flower has. We have long since surpassed this idea and currently we follow an evolutionary tree model. Linnaeus’s binominal system is still successful as it is standardised and relatively easy to remember.
Twenty-first century botanists have a new tool: rapid DNA sequencing. Indeed, DNA sequencing has been around since the 70’s, and its contribution to science cannot be denied. With rapid DNA sequencing botanists now have a relatively low-cost tool at their disposal to retract the DNA from a plant and therefore another means for classification. Morphology, in biology, is the study of the size, shape, and structure of animals and plants and this has long been the criteria for classification. The key in tree identification books is a good example of this there you look at bark (colour, texture etc.), leaf arrangement (alternate, opposite etc.) and leaf form (lobed, palmate etc.) to determine the species. With the advent of rapid DNA sequencing all this is changing. Subsequently, in recent years many plants have been reclassified, let’s have a closer look at a few examples:
Nothofagus, our southern beeches were initially described as Fagus and it wasn’t until 1851 that botanists (Blume) reclassified it under its own Genus. Nothofagus, are trees known to grow in Southern South America, Australia, New Zealand, New Caledonia and Papua New Guinea. Nothofagus has long been used as a perfect example of our links to the former supercontinent Gondwana and in understanding continental drift. It was previously subdivided into three subgenera based in how the pollen looked under a microscope, namely Fusca, Menziesii and Brassii. In 2013 it was proposed that it is now subdivided into 4 subgenera: Nothofagus (exclusively in South America), Fuscaspora and Lophozonia (represented in South America, Australia and New Zealand), Trisyngyne (The tropical beeches surviving in the Highlands of New Caledonia and Papua New Guinea).
Our Kānuka, initially described as Leptospernum ericoides, but renamed in 1983 as Kunzea ericiodes. In the past Kānuka, alongside Mānuka has had a bad reputation to farmers as being invasive to grassland, even today whole hillsides can be seen that are cleared from Kānuka and Mānuka. In 2014 Peter de Lange completed a study regarding Kunzea species in New Zealand, it concluded there are actually 10 Kunzea species as opposed to just one. I was fortunate enough to attend a presentation by de Lange, and I must say that his findings are undeniable. Not just through DNA sequencing but also through mātauranga (Māori traditional knowledge) and historical scientific facts.
What we know here in NZ as a “Macrocarpa”, is no longer classified as a Cupressus. Through DNA sequencing it has been found that the “New world” species of Cupressus are actually not closely related to their Eurasian counterparts and are now classified as Hesperocyparis.
And lately, our Kohekohe once known as Dysoxylem spectabile is now renamed Didymocheton spectabilis, yes, its species name is changed somewhat too! Kohekohe is the most southern member of an otherwise tropical family of trees, stretching from New Zealand, Australia the Pacific Islands to South East Asia, India and Sri Lanka. Once again through DNA sequencing It was found that Kohekohe is closely related to species from the South Pacific Islands.
Name changes are a funny one, taxonomy is the practice and science of categorization or classification. And this actually follows international guidelines as described in the International Code of Botanical Nomenclature. Personally, when I become aware of such a change, it intuitively annoys me, shaking the foundations of my botanical knowledge. However, when you dig a little deeper, the accompanying DNA sequencing proof, make sense. I do hope the botanist can drip-feed us in terms of name changes though, just so my brain can keep up. I guess, we will have to learn about what we already know.
References:
Poole, A.L. 1987: Southern beeches. New Zealand Department of Scientific and Industrial research.
John A. Wardle, 1984: The New Zealand Beeches, ecology utilization and management. NZ Forest Service, Wellington.
de Lange P. J. (2014). A revision of the New Zealand Kunzeaericoides (Myrtaceae) complex. PhytoKeys, (40), 1–185. https://doi.org/10.3897/phytokeys.40.7973
Nomenclatural adjustments in Juniperus deppeana: Juniperus deppeana var (phytologia.org)
Confirmed polyphyly, generic recircumscription and typification of Dysoxylum (Meliaceae), with revised disposition of currently accepted species Laura Holzmeyer,Frank Hauenschild,David J. Mabberley,Alexandra N. Muellner-Riehl First published: 30 October 2021 https://doi.org/10.1002/tax.12591