Plant Nomenclature for the Home Gardener

Back in the olden, olden days, the names of plants were a mishmash of terms and words that would make your head spin. Before Linnaeus came along in the mid-1700's, a typical plant name might be Arbutus caule erecto, foliis glabris serratis, baccis polyspermis meaning Arbutus tree with upright stems, hairless, saw-toothed leaves and many-seeded berries. Wow! Imagine memorizing a name like that for every plant in your landscape.

Fortunately, with Linnaeus help, scientists developed a much simpler process called binomial nomenclature which, as the name implies, consists of only two words to identify any living organism, plant or animal. There is a regular hierarchy of names that can convey a lot of information about a particular plant. Professionals called taxonomists spend their lives figuring out which plants belong in which categories. But for the home gardener, fortunately, the changes they make only occasionally affect us.

The range of names that are used to identify plants include:

• Family
• Genus
• Species
• Botanical Variety
• Cultivar
• Common Name

Nomenclature

The botanical name is the internationally rec­ognized name for a particular plant. Its stem is usually Latin, Greek, or a proper name or de­scriptive term, and has a Latinized ending. The botanical name consists of two names: the first identifies the genus, and the second (specific epithet) identifies a particular member of the genus. Together the genus and specific epithet constitute the name of the species. The first letter of the genus name is always capitalized, and the specific epithet is commonly written in lower case letters. The species name is underlined or italicized (for example, Cotoneaster horizontalis).

The species (plural also species) is the basic unit in a classification system whose members are structurally similar, have common ancestors, and maintain their characteristic features in na­ture through innumerable generations.

The genus (plural genera) may be defined as a more or less closely related and definable group of plants comprising one or more species. The unifying characteristic of a genus is a similarity of flowers. A group of closely related genera is called a family. The botanical name of the family is usually recognizable by its —aceae ending. The stem of the name is the name of one of the genera within the family. For example, Cornaceae is the family name in which Comas is a genus.

A variety is a subdivision of a species, and ex­hibits various inheritable morphological charac­teristics (form and structure) that are perpetuated through both sexual and asexual propagation. A variety is designated by a trinomial (three names). The varietal term is written in lower case and underlined or italicized. It is sometimes writ­ten with the abbreviation var. placed between the specific epithet and the variety term (for example, Junipemus chinensis sargentii or Juniperus chinensis var. surge n hi).

A culfivar (the term is a contraction of “culti­vated variety”) is a group of plants within a par­ticular species that is distinguished by one or more characteristics (morphological, physiologi­cal, chemical, etc.), and that, when reproduced sexually or asexually, retains these characteristics. The cultivar term may be one to three names. Each name in the term begins with a capital let­ter. The term is commonly written inside single quotation marks (as in this book), but it may be preceded by the abbreviation cv,, and is not un­derlined or italicized (for example, Forsythia vii’­idissirna ‘Bronxensis’ or Forsythia viridissima cv. Bronxensis).

A clone (or don) is a group of plants that origi­nated from a single plant, and have been propa­gated by asexual means (cuttings, grafting, division, budding and layering, etc.) to maintain the exact characteristics of the parent plant.

The name of a hybrid is preceded by a multi­plication sign (x) between the generic name and the specific epithet- The names of the parents are listed with the multiplication sign between them. For example, Symphoricarpos x chenaultii is a hybrid of Symphoricarpos orbiculatus x Sym­phoricarpos microphyllus. In the case of Sytnpho­ricarpos x chenaultii ‘Hancock’, ‘Hancock’ is a cultivar of the hybrid plant.

Each plant that has been recognized and de­scribed has only one valid name — its botanical name (consisting of the name of the genus and the specific epithet). This binomial system of nomenclature was created by Carolus Linnaeus (1707-1778) in his book Species Plantarum (1753). The nomenclature is controlled by the Interna­tional Association for Plant Taxonomy, which is­sues an International Code of Botanical Nomencla­ture that is strictly adhered to throughout the world. The International Code if Nomenclature for Cultivated Plants, which governs the rules for naming cultivars, is issued by the International Union of Botanical Sciences. Both of these Codes are revised periodically.

The botanical name for each of the plants de­scribed in this book appears on the upper left of the page, followed by the most often used com­mon name and the hardiness zone or zones in which the plant can be successfully grown. These are followed by the family name and, in some cases, by other common names and the obsolete botanical name or names under which the plant may be listed by certain nurseries or garden centers.

The nomenclature can become confusing in at­tempting to identify a particular plant. For this reason, you should always use the botanical name when ordering a plant. (It is also helpful to be familiar with the obsolete botanical name or names under which the plant may be listed.) Be­cause common names are not governed by any formal code of nomenclature, and because there are frequently many common names for one species (some of which are obsolete), the use of a common name can lead to mistaken identities.

For information aboot nurseries and other sources of plants described in this book, consult your county Extension adviser or the horticulture department of your state land-grant university.

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