Plant Names

In the world of plant names, science rules.

​Depending on where you live, a plant’s common name can be pretty much anything. It’s not uncommon for a single plant to have several different names, which can be confusing.

Imagine my dismay when I learned that the sunny blue cornflowers I selected for my wedding were also known as bachelor buttons.

Common names are usually region specific. A plant’s scientific name, however, stays the same all over the world.

Cornflower (Kiran Jonnalagadda) CC BY-SA 3.0

The science of names

Certain scientists, called taxonomists, love to classify things. They use a system of names that show how closely everything is related to everything else, based on shared characteristics. This all started way back in the early BC’s with Dioscorides (die-oh-score-ih-day) and Theophrastus (thee-oh-frass-tis), but Pliny the Elder’s encyclopedic Naturalis Historia (77AD) is recognized as the first attempt at classifying plants (and every other living thing known at that time). It wasn’t until 1753, when Carl Linnaeus published Species Plantarum (“The Species of Plants”) that the world had a comprehensive plant naming system. Since Latin was the language of educated Europeans at that time, it is still used today as the universal scientific language. If you see a plant name followed by an L., you will know it was classified by Linnaeus.

Basic taxonomy

This sorting by shared characteristics files everything into a series of increasingly specialized categories. Here is a list, using the standard garden tomato as an example: 

• Domain (Eukaryota) - Living cells with nuclei
• Kingdom (Plantae) - Plants
• Division (Angiosperms) - Seed-bearing plants
• Class (Magnoliopsida) - Flowering plants
• Order (Solanales) -
• Family (Solanaceae) - Nightshade
• Genus (Solanum) - Woody nightshade (potato and tomato)
• Species (S. lycopersicum) - Garden tomato

Yellow cherry tomato

If you have a hard time remembering the order of these classification words, try this popular mnemonic: Dear King David came over from Great Spain. Or you can try making up your own!

Under each of these headings, there can be subcategories and super-categories, but don’t let that scare you off. The most important information is what’s on the label. The two Latin words next to a plant’s common name tell you the genus and species of that particular plant.

Genus and species

The first word is the genus, or generic name. This word is always capitalized, and either underlined or italicized. The next word, in lowercase, tells you the species, or epithet. The species is also either underlined or italicized, but it is not capitalized. The genus and species can provide basic information of growth habits and good cultural practices. Once you have a plant’s genus and species, you can get even more information from its variety or cultivar name.

Variety

When a species has a naturally occurring mutation that reproduces consistently, it is called a variety. To indicate a variety, the abbreviation var. is found after the species name. The variety name is not italicized, underlined, or capitalized. Taking the example above one step further, with a red cherry tomato, we have S. lycopersicum var. cerasiforme.

Cultivar

When a mutation occurs as a result of human intervention, be it through selective breeding, cultural practices, or genetic engineering, the plant is called a cultivar. Cultivars are “cultivated varieties” and you will see cv., followed by a name in single quotations to indicate the cultivar. Cultivar names are capitalized, but they are never underlined or italicized. Again, we can use the above example to see the name of my favorite yellow cherry tomato, the Sun Sugar (S. lycopersicum cv. ‘Sun Sugar’).

Scientific plant naming - then and now

In its early stages, plant taxonomy was based on obvious shared characteristics, such as whether a plant produced seeds or spores, was vascular or non-vascular, and whether it was herbaceous or woody. This method worked well enough for a time. With the advent of genetic testing, plant naming, or botanical nomenclature, has gone through some changes. This is why you may see two different Latin names for the same plant. In fact, there are currently several different classification systems vying for dominance in the world of plant names, which is why it took me so long to write this post!

The most important information to take from this post is to take the time to read those plant labels. Reputable growers are far more likely to sell you what is described on the label. Unreliable growers, not so much. Reading the label can give you a starting point when researching plants that you would like to grow in your garden or foodscape.