Warning – pretty dry entry ahead.
I wasn’t exactly looking forward to my Botanical Latin class on the hot, sunny afternoon of July 6, 2015. Why was I taking it? It’s a required course for the Master Gardener program at the U of S. This class actually turned out to be one of the most valuable classes I’ve taken to date. It was even interesting and entertaining, thanks to my favourite gardening instructor, Vanessa Young.
Today I’m at home sick and all of the work that I could be doing is not at home with me. Why not take this opportunity to do some learning? I decided that I need a refresher on botanical Latin (binomial nomenclature – the system of naming plants). Sure, we can use common names when referring to plants, but I want to make sure we are being as specific as possible when discussing our plants on this blog. When possible, I’ll try to give the Latin names for whatever plants I’m talking about. That way, if you decide you want to find that plant for your own yard, you can find the exact same plant.
The first word refers to the genus. You can think of the genus as the plant family’s last name. For example, Jones is the last name for all the people in the Jones family. This plant family’s name is Trifolium and tells us that any plants in this family are very closely related. It is always capitalized and italicized. If handwritten, it’s underlined. If I was using this genus name repeatedly, I could abbreviate it T. rubens after I write it out the first time. Sometimes the genus can be used as its common name, such as the petunia (Petunia hybrida), delphinium (Delphinium albiflorum), and clematis (Clematis alpina).
The second word is called the specific epithet or the species. Specific epithet is a better term to use because the two words together (i.e., Trifolium rubens) indicate the plant species, but sometimes people refer to the specific epithet as the species…. just to make things confusing.
The specific epithet is the equivalent of a person’s first name. Let’s say we have Trifolium rubens and Trifolium gemellum. We could say that these are two siblings that are very closely related but are different enough that they deserve different names. Plants with the same specific epithet can interbreed among themselves. The specific epithet might come from the plant’s Latin or Greek name, refer to the geographical area it came from, describe a physical characteristic of the plant, or honour a person. Rosa arkansana is a species of rose originally found along the Arkansas river, while Rosa woodsii is a species of rose that grows on the edge of a forest.
Sometimes the genus is known, but not the specific epithet. In that case, you would write the genus name, followed by “sp.”. For example, you could write Trifolium sp. to show that you know it’s a Trifolium but you aren’t sure about the specific epithet.
In rare cases you might see a third part of a scientific name, such as Rosa arkansana Porter. This tells you who officially named the plant. I haven’t seen this very often as an amateur gardener.
Varieties vs. Cultivars
This is where I tend to get confused. A group of plants forms a variety when they grow wild in nature and have a unique characteristic from the rest of their species. The handout from my class gives the example of the chokecherry Prunus virginiana, which is a familiar native cherry. In eastern North America the fruit is bright red, but in western North America, the fruit is very dark purple to black. Otherwise, the two plants are identical. In order to differentiate the two, the western chokecherry is called Prunus virginiana var. melanocarpa (melano = black; carpa = fruit).
Cultivars are often confused with varieties. Cultivars refer to a group of plants that originated naturally or were developed using human activity. A cultivar requires human intervention in order to reproduce. Prunus virginiana var. melanocarpa ‘Schubert’ (the Schubert chokecherry) is a popular cultivar here in the prairies. It differs from other chokecherries because its leaves turn purple in the summer. It was found in the wild, then humans reproduced it and they continue to cultivate it today.
According to my class, true botanical varieties are pretty rare. If you have to guess on whether the name refers to a variety versus a cultivar, you are far more likely to be correct if you guess that it’s a cultivar.
An “x” in a name tells you that a plant is a hybrid. A hybrid is an individual plant that has been produced using two genetically different plants. In this case, you won’t often find the full lineage of both parent plants but you will at least know that it’s a hybrid.
The Fun Stuff
I find binomial nomenclature super interesting because the structure of a word can tell you about the plant itself. You might not know what a Trifolium rubens is, but you can quickly learn about the plant by studying the word.
Tri = three; Folium = foliage = leaves
Trifolium = three leaves
Rubens sounds like rubies. Rubies are red.
Trifolium rubens = a three-leaved plant that is red.
(It’s actually a red-flowering clover. Cool, hey?)
(Information taken from “Botanical Latin for Master Gardeners” from the University of Saskatchewan.)