One of the most fun and interesting parts of the plant hobby is learning all the scientific names.  Many times, these names are hard to pronounce as they are in Greek or Latin, or Latinized names from other languages (when named after a person or place for example). One of the most frustrating things to experience, is when the names suddenly, without warning, change! All that hard work down the drain. Scientists are not doing this to make our lives difficult, however. It generally reflects some new learning or discovery. 

Taxonomy is the branch of science that names and groups organisms according to their characteristics and, more recently, evolutionary history. Naming has a long history, starting with Aristotle around 350 B.C. He classified things as either animals or plants, and there were three types of each. There was no thought of evolutionary relationships back then, as this phenomenon was not formally (and correctly) described until Darwin did in 1859. In the 1700s, Carl Linnaeus designed a system that grouped organisms into hierarchical categories based on morphology (shape). This is the familiar Kingdom, Phylum (Division in plants, fungi, and bacteria), Class, Order, Family, Genus, and specific epithet. Groups of international scientists have more recently tried to agree on one system. You no longer see Divisions in plants, for example. Each species has only one two-part name. This was all part of Linnaeus’s design. Just like many human names have two parts, first and last, scientific names consist of the Genus and specific epithet. This is referred to as “binomial nomenclature.” For example, the Red Maple is known as Acer rubrum.

In my example, notice that there were two ways to refer to one of our favorite trees. We had the common name, Red Maple, and the scientific name, Acer rubrum. Although common names may be easier to remember, the disadvantage is that they can vary around the world, or in different locales. Many times, when I was doing scientific research on native fish in Pennsylvania, you would go over a mountain and find the people in that valley referring to the fish with totally unique names. This made it very difficult to communicate and find the species we were looking for at the time. Scientists, and serious plant hobbyists, prefer the scientific name. These are the same throughout the world. This makes for more efficient communication and eliminates any confusion. When plant collectors pay a large sum of money for a new plant, they want to be sure they are getting exactly what they wanted. Once again, scientific names are the way to ensure this accuracy.

There are some additional names that can be used. There are more categories added to the Linnaean hierarchy from top to bottom. These names may include subspecies, subgenera Superorders, etc., all the way up. With plants, you may see variety names following the formal classifications. For example, our red maple has a variety called Acer rubrum ‘Autumn Flame.’  These cultivated varieties will show consistent phenotypes (physical traits) and are put in single quote marks.

So, if all this is true, then why do scientific names of organisms change? Well, simply put, because some scientist, somewhere, learned something new about our plants that changes their evolutionary relationships. These new discoveries may warrant name changes, which is like making corrections to a rough draft of a report. As a consequence, many times this results in a domino-effect resorting of our plant species. To the public, this just seems like a shuffling of the deck, but it is not. Once again it relates to the rules of Botanical Nomenclature set up by one of those international scientific committees. The new information necessitates the changes we see and produces a more accurate grouping of our plants. 

Some modern examples of this is the famous Christmas cactus. These were in the genus Zygocactus, which then was changed to Schlumbergera. Our good friends known as Pothos have undergone numerous name changes, and, if I had to guess, will continue to do so. The most recent victims are the beautiful African Violets! I was at the Connecticut Flower and Garden Show this past February and noticed the name changes there.  he African Violets, which were in the genus Saintpaulia, are now Streptocarpus, and the Streptocarpus are now Streoticarpus.

African violet in pot
A beautiful African Violet cultivar ‘Roulette’ seen by the author at this year’s Connecticut Flower and Garden Show. It was labeled with the new Genus name Streptocarpus, which used to belong to the Cape Primroses. Photo by mrl2023.

Normally, this is just a frustration to many people, but they quickly learn the new names. For super popular plants like African Violets, this can take a long time to fix. Many African Violet collectors I know were not even aware of the change. The only other time that name changes can be a problem is when the scientific name becomes the common name. This happens many times for our plants. One of the best-known examples is the Rhododendron. This is the genus name as well as the common name, but there has not been any change there.  Were those plants to undergo a revision which resulted in a new scientific name, I do not think the common name would change, which can cause confusion.

So why the sudden changes? Well, we (humans) are getting much better at telling the different species apart. DNA technology and further understanding of the genome of the plant of interest have us teasing out the subtle differences between closely related, phenotypically similar species.  Many times, the scientists knew the groupings were inaccurate, but no one had the time or evidence to separate them into species (like with the Pothos, for example).

A nice healthy specimen of Neon Pothos for sale at a garden center. The Pothos have undergone many Genus-level name changes over the years. Photo by mrl2023.

So, my advice? Enjoy the change. Look at it as human plant knowledge just got a whole lot more accurate. Occasionally, scientists do not agree on the changes due to conflicting evidence. This can be fun to watch them battle it out, but sooner or later it gets resolved. For my beloved African Violets, this will take some time. I will miss the old name I have known my whole life.  Streptocarpus are one of my absolutely favorite plants, and now that name resides with one of my other favorites – the African Violets. As us plant collectors get used to the new names, this will certainly provide some confusion. The Gesneriads, or plants in the family Gesneriaceae, like African Violets and Cape Primroses (using common names), have been the subjects of many revisions lately. I would expect some more, so try and roll with it!

Matt Lisy