Botanical Nomenclature- It's Not as Bad as You Think!

by Kathy Musser, Cloverleaf Herb Farm
previously published in The Essential Herbal Magazine (Nov/Dec '18)

If you deal with plants long enough, either as a serious hobbyist, or a professional,  eventually you run up against botanical nomenclature.  I know people who have studied plants extensively, but stopped in their tracks when it came to learning scientific names. My introduction came during courses I took at Longwood Gardens. We had to learn the botanical name, and correct spelling, for each plant we studied! And although, after more than twenty years, I don't remember them all, I learned enough about the system to make it easy to categorize many plants and also to understand the basis for many scientific names. This article will be a primer for understanding the system of botanical nomenclature,  how to navigate it in researching plants and some tips for recognizing recurring words and descriptions.

Botanical nomenclature is a uniform system for naming and classifying plants. It begins with large groups of plants with certain similar characteristics and gradually refines the classification down to a specific plant. Why was this done? If you visit several greenhouses, you might see the same plant listed under different common names. I have this experience nearly every year. A customer comes in and asks for a plant by a certain common name. If we don't have it, I ask for a description. Often, we have the plant although we list it by an alternate common name. Sometimes, plants have different common names in various locations or have an 'old-fashioned' name that has been modernized. It can be confusing when the same plant has multiple names. 

Across the spectrum of groups of plants, the importance of using botanical names varies greatly. With many annuals, herbs and more familiar perennials, common names often suffice. Using botanical names might be more important in choosing trees or shrubs, particularly if you're looking for a specific variety, identical plants for a hedge or windbreak or a plant with definite characteristics. 

The system of botanical nomenclature was developed by a Swedish botanist  - Carl von Linne, although his name is often written in the Latin form as Carolus Linnaeus. Latin names for plants may denote geographical distribution,  cultivation, chemistry or even uses of a specific plant. The system is uniform throughout the world, and a botanical name will identify the same plant here, or in France, Brazil or Latvia. The system is ever evolving, so there are periodic name changes to correct past errors or based on new information.

Each plant is given a two part name. The first word refers to its genus - a group that has common characteristics. The genus name is capitalized. Following it is the species, or specific epithet, which begins with a lower case letter. This part of the name is more specific to distinguish plants within a genus from one another. Sometimes there is a variation within a species, like a different color, a better flower or variegation. This name would be written Genus species var.(for variation.) There are also cultivars or cultivated varieties. These plants do not occur in nature, but have been developed by man, and are maintained by gardeners. They can be designated by cv., or more commonly by putting the cultivar name in single quotes. Hybrids are a cross between two species and are designated by an X. For example, Lavandula x intermedia 'Grosso' is a hybrid variety of lavender, commonly called lavandins, with the cultivar name 'Grosso' describing a large plant with long-stemmed purple flowers.

Even a limited knowledge of botanical nomenclature can be helpful. Many gardeners are anxious to provide host plants on which butterflies lay their eggs. Milkweeds are hosts for monarch caterpillars. If you recognize that the genus Asclepias denotes varieties of milkweed, you'll know that Asclepias tuberosa (butterfly weed), Asclepias incarnata (swamp milkweed) or Asclepias syriaca (common milkweed) will all serve as host plants for monarchs.

When I was in high school, (a very long time ago) Latin had fallen out of favor as a language to be studied. If I had known I'd wind up in a horticultural career, I would have studied Latin. But even without that background, there are recurring words used to describe many plants in the system of botanical nomenclature. If you become familiar with them, it helps to identify many common herbs.

officinalis/officinale-meaning the plant had commercial value, generally as an apothecary plant

     Rosmarinus officinalis=rosemary

     Salvia officinalis=sage

vulgaris/vulgare-common or ordinary variety

     Thymus vulgare=thyme

annua/annuum-an annual plant

     Artemisia annua=sweet Annie

procumbens/prostratus-creeping type of plant

     Rosmarinus officianalis 'Prostratus'=creeping rosemary

tinctorius-refers to plants used in dyeing 

     Carthamus tinctorius=safflower

graveolens-heavily scented

     Anethum graveolens=dill

odorata-sweetly scented

     Galium odorata=sweet woodruff

phylla-means leaves and other words or prefixes are added to further describe foliage

     microphylla=small leaves

Several words are used to describe foliage or flower color and are repeated throughout the system

     ruber=red                          aureus=golden

     virens=green                      niger=black

     alba or albus=white