What’s in a Name?

It would be hard to imagine life without names, for names represent a “short-hand” method of identifying things, including people. Yet, names can lead to confusion because in many cases there is a good deal of overlap. For example, a first name along with a surname is the most common way to differentiate one person from another. However, according to the most recent census, more than 2.7 million people in the United States share the surname of Smith. James is the most common first name among men and is shared by 3.3 percent of all males. If we can assume half of the Smiths in the United States are male, then there must be 44,550 men in our country with little more in common other than the name James Smith.

Using common or regional names to identify plants can be similarly confusing, though not to quite the same magnitude. First, the same plant might be known by a different common name in different regions of the world. For example, the common name “Blue Bell” refers to a plant in the genus Campanula in Scotland, Endymion in England, Eustoma (and others) in the United States and Hyacinthus in France. Conversely, different plants might be called the same common name in different regions of the world. At last count, there were eight different plants in the United States that (in some part of our country) go by the name “Creeping Charlie.” Clearly, a more precise naming system had to be developed to differentiate one plant from another, and the scientific naming system was thought to be the answer.

Until the middle part of the 18th century, the scientific system of plant nomenclature simply involved using Latin words (mostly adjectives) to completely describe the plant. The common flower carnation had the unbelievably complex scientific name of Dianthus floribus solitariis. squamis calycinis subovatis brevissimus, corollis crenatis. Obviously, students of plant materials were at quite a disadvantage in those days. In 1753, a gentleman by the name of Carl von Linne (who later changed his own name to Carlos Linneas) changed all of that when he proposed the binomial system of plant nomenclature in his book Species Plantarum. Essentially, he proposed that plants should receive two Latinized names, one representing the genus and the second the specific epithet. Together, these two names scientifically identified a species, and this system is still in use today. Carnation went from the unworkable name listed above to simply Dianthus caryophyllus.

In the scientific naming of plants, the genus is loosely defined as a closely related and definable group of plants comprising one or more species. In the case of genera (e.g. Ginko), there may be only one species; in the case of others (e.g. Rosa), there may be hundreds. Genera of plants often are named in honor of a person. For example, the genus Begonia, which contains more than a hundred species, is named in honor of Michel Begon (1638-1710) who was governor of Santo Domingo and a great supporter of botanical studies. At other times, the genus name simply describes in Greek or Latin terms certain attributes of its members. Campanula comes from the Latin word for bell and is the name given to the genus to which the bell flowers belong.

Perhaps, the most important classification is the species (genus and specific epithet together), and this term is more of a concept than an absolute entity. Because species must vary from one another by some “marked or essential feature,” individuals might disagree relative to what is a marked or essential feature. In fact, the appearance of individual members of species do vary to quite an extent as evidenced by humans. Specific epithets usually are adjectives used to describe the species in Latin terms (e.g. purpurea meaning purple, procumbens meaning prostrate or odoratus meaning fragrant). One of my favorite illustrations of a descriptive specific epithet is for Larkspur. It has the scientific name of Consolida ambigua; the latter literally interpreted means “not sure” or “uncertain.” Evidently, taxonomists are not too proud to admit when they are stumped.

In nature, plant species often are subject to specific environmental conditions resulting in a variant form of the species that can reproduce itself without human intervention. The result is known as a “botanical variety.” For example, Gleditsia triacanthos is the scientific name for Honey Locust, a common woodland tree that bears thorns in great profusion. Somewhere in antiquity a truebreeding, thornless strain appeared. This variant represents a botanical variety. The Latin word for thornless is inermis which, literally interpreted, means “unarmed.” Therefore, the complete scientific name for the botanical variety is Gleditsia triacanthos var. inermis, or Thornless Honey Locust.

With horticultural and other cultivated plants, it is common practice for humans to produce their own variants through genetic manipulation or cultural technique. These man-made variants are known as “cultivars,” short for cultivated varieties. For example, selections made from Thornless Honey Locust have produced improved forms of this botanical variety. The cultivar ‘Sunburst’ is a good example. In addition to being thornless, it has new growth which emerges golden yellow and ultimately changes to bright green by mid-summer. The scientific name of this “man-made” variant would be Gleditsia triacanthos var. inermis ‘Sunburst,’ or Sunburst Thornless Honey Locust. Please note that unlike botanical varieties, cultivar names are not italicized but are set off in single tick marks. Cultivars often are sterile and must be vegetatively propagated. At other times, they are hybrids whose genetic makeup must be reconstituted each generation by crossing two specific parents. Or, they might “breed true” from viable seed. An example of the latter would be Coreopsis grandiflora ‘Early Sunrise’, and improved, semi-double form of Lance Coreopsis that breeds true from seed.

So, the next time you shop for plants, look at the scientific name on the care tag. It is included not to impress you with Latin but to allow you to be certain that the plant you select is actually the one you wanted to buy. Familiarity with scientific nomenclature will not only make you a wiser consumer, but also it will make you a better gardener as well.

David Trinklein, Department of Horticulture, UMC, (573) 882-9631