Why Plant Catalogs Use Confusing Latin

Marc Montefusco
Frederick County Master Gardener Program

Scientific names, or Latin names, seem somewhat confusing at first. But there's a reason to use them, and once you get into the habit, you may never go back. Here's why.

Many common names, like "daisy" or "milkweed," can refer to several different plants. On the other side of the coin, some plants can have many different common names. The names "Bluebeard," "Blue-spirea," and "Blue-mist shrub," for example, all refer to the same flowering shrub. When we see a plant that we like, we often ask its name so that we can own it for ourselves. If the name you're given is "Rock rose," for instance, you may wind up with something very different from what you expect.

In the 17th century and earlier, when plants were widely used as medicine, getting a name wrong could have fairly serious consequences. For this and other reasons, a Swedish botanist named Carl Linné (known to his educated friends as Carolus Linnaeus) invented a comprehensive scheme for naming all living creatures, at the same time grouping them according to natural relationships. This system, which is still in use, is called binomial

nomenclature - "binomial" because each organism has two names that identify it uniquely, and "nomenclature" because it sounds cool. (Just kidding!) The scientific name for the black walnut is Juglans nigra. The first of the two names - Juglans -- is the "generic" name. There are several different kinds of walnuts in the genus Juglans, and all share the same generic name. The second name is the specific, or species, name. In this case, "nigra" isLatin for - you guessed it - "black." Take both names together and you've got the black walnut, with no chance for confusion.

Are you with me so far? Good, because it gets a little more complicated. Observers of plant and animal life often notice that some populations of a species share a slightly different set of characteristics than the average run-of-the-mill specimen. Let's see how this might affect a scientific name. One common genetic quirk among flowering plants is called "doubling," where the normal number of petals in the flower is increased, in some cases by many times. The Carolina Rose, also known by the common name Pasture

Rose is called, in binomial nomenclature, Rosa carolina. There is naturally occurring double form of this rose, and its scientific name is Rosa carolina plena ("plena" from the Lain word meaning "full.") Rosa carolina plena is called a variety, and should probably be written Rosa carolina var. plena, where "var." is short for variety.

One more complication, and then we'll roll Carolus Linnaeus (known to his non-scientific friends as "Charlie,") back into his grave. Sometimes an individual plant shows some exceptional characteristic: it's very short, or has large flowers, or especially colorful foliage. In this case, the plant itself, and all its genetically identical offspring, can be given a cultivar name. 

One familiar example might be the red-leaved Japanese maple "Bloodgood." Its full name is Acer palmatum "Bloodgood." Cultivar names are very important to gardeners, because they identify the exact characteristics of a particular plant. If you don't think they're important, consider the fact that there are well over 150 cultivars of Japanese maple available commercially, and all of them are different.

To sum it all up, scientific names help gardeners get the exact plants they want, and help them communicate accurately with other gardeners. Give binomial nomenclature a try. Don't worry about pronunciation, since the last native Latin speaker is no longer around to correct you. You'll astound your gardening friends, and you might even decide that it's fun.

Read other articles by Marc Monefusco