Thursday, October 25, 2018

Why We Use Botanical Nomenclature - A Guest Post By Christine Wegman

The topic of botanical nomenclature is always an important topic in terms of our mission to educate our members and the public. we hope you enjoy Part I of Christine Wegman's essay. Please feel free to leave questions and/or comments below.

The reason we use botanical nomenclature to identify a plant is that it eliminates a lot of confusion.

I love to tell this story about my mother.  She was a wonderful gardener, that enviable person who could make anything grow.  She made beautiful gardens in such diverse climates as southeastern and western Australia, and the U.S. mid-Atlantic and Pacific coast.  Mother was aware of the existence of botanical nomenclature, but she had no interest in it.  The closest she came to applying it to a plant was the word “japonica” which she used rather indiscriminately for three different plants:  camelia, pieris, and flowering quince.  We weren’t always sure which one she meant.  And that, of course, is precisely the reason why botanical nomenclature has become important.  If we use it correctly we don’t have to wonder about which “japonica” we are referring to. 

I still love the traditional common names for plants and I continue to use them along with the Latin names.  I remember my Mother holding a snapdragon flower horizontally and pinching it to illustrate its resemblance to a snapping dragon.  This charming analogy is utterly lost in its botanical name, Antirrhinum majus.  But things were simpler in the good old days because they really were simpler.

The 19th century was a time when legendary European plant explorers discovered many new species of plants in Asia and introduced them into cultivation in Europe and America.  Many new Asian discoveries were relatives of plants in the west.  Native American azaleas, witch hazels, dogwoods and hibiscus – to name a few -- all have East Asian counterparts.  Specific nomenclature is needed to distinguish these different forms of the same plant. 

In our own time, the amazing biological research that has led to new life saving pharmaceuticals also led to new and faster ways for breeders to develop and introduce new plants into the market.  Hundreds (probably thousands) of new plant varieties, and even crosses between different plant species, have made their appearance.  A good case in point is the wonderful Itoh hybrid peony, which produces the beautiful leaves and flowers of a tree peony on a perennial plant that is not subject to the vicissitudes of late spring frosts.  The traditional common names are just not specific enough to properly identify the vast numbers of new plants and hybrids that exist.  Hence the need for a more organized way to deal with the situation. 

The system we use today was invented by Carl Linnaeus, a Swedish botanist who lived in the 18th century.  He used Latin names because Latin was the universal language of science and learning in Europe at the time, thus a plant name would be the same in any country.  This was a tremendous advantage to the relatively small group of botanists and plant enthusiasts because everybody knew exactly what plant they were talking about, even though they lived in different countries and spoke different languages.  That same advantage applies today.  When you use the correct botanical name for plant identification, everybody knows exactly what plant you mean. 


Plants are grouped into divisions that describe their characteristics.  The system is hierarchical comprising three groups:  family, genus and species.  Family is the largest group, species the smallest and most specific.  When we identify plants we generally only use the last two:  genus and species.  Hence, the term, binomial (or two names).  So, my mother’s “japonicas” become Camellia japonica, Pieris japonica, and Chaenomeles japonica (quince).  The names are written in italics, or when handwritten they are underlined.  Capitalize the name of the genus (Camellia) but not the species (japonica).

If you don’t know the botanical name for a plant, it is easy to find on the internet.  Just enter the phrase “botanical name for snapdragon” and it will give you the answer, Antirrhinum majus.  This binomial name is the first part of a plant’s proper identification.  When you are entering a plant in a horticultural flower show 5 points are awarded for a “plant completely identified with genus, species, cultivar, as appropriate.”  It may only be 5 points, but it may well be the difference between a ribbon and not.  And, plants that are not correctly identified are not eligible for an NGC Top Exhibitor award. 

Next month I will write about hybrids and cultivars, and how they are noted in a plant’s proper name.

Christine Wegman is a Rock Spring Garden Club member in National Capital Area Garden Clubs' District III.  She is one of the go-to 'hort' experts in her club. Christine and her husband, Charlie Flicker, are avid and generous gardeners and have cultivated a delightful garden (for any season) in Arlington, Virginia. 

photographs by Evie Shaffer and Sarah Sosiak via Unsplashed

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