For thousands of years people have given names to their local plants as an aid in identification. The common names were usually based on local conditions, language, plant use, general appearance, and other subjective criteria, and often only recognized in the immediate area where they were originally coined. As a result, the use of common names to identify plants can create a great deal of confusion.
- Completely different plants might share the same common name. The common name “Red Root” is used for all of these different plants: Ceanothus americanus (drought-tolerant perennial shrub with white flowers), Iris versicolor (lakeshore perennial with blue flowers), Lachnanthes caroliniana (invasive aquatic plant with wooly-looking white flowers), Potentilla erecta (herbaceous perennial with yellow flowers), and Sanguinaria canadensis (herbaceous perennial with white and yellow flowers).
- In different areas, the same plant might have different common names. Iris versicolor, mentioned above, is also known as American Blue Flag, Dagger Flower, Dragon Flower, Flag Lily, Harlequin Blueflag, Liver Lily, Poison Flag, Snake Lily, Water Flag , Water Iris, fleur-de-lis, and flower-de-luce.
- One common name is used to describe a large number of related, but unique, plants. There are over one hundred species of wild rose, and thousands of cultivated rose species, subspecies, varieties, hybrids, and cultivars. Which sweet-smelling rose was Shakespeare writing about?
- Many plants do not have a common name. This is especially true for rare plants or those without ornamental or commercial value.
Scientific Plant Names
To prevent confusion over common names, and to identify previously unnamed or newly-discovered species, the binomial system of names was created for identifying plants and animals. The binomial system is used to create a unique “scientific name” for each species, a name that is the same for all locations and persons and identifies a single, specific organism.
The binomial system uses each plant’s genus and species names to construct the unique scientific name for that individual plant. An example of a binomial scientific name is Acer rubrum, a plant commonly called Red Maple.
The first part of the scientific name is the name of the genus to which the plant belongs. A genus is a group of closely-related plant species sharing similar, but not identical, traits. For example, Acer is the official name of the Maple genus.
The second part of the scientific name is the species name, also called the specific epithet. All plants which are fundamentally alike are part of the same species. In our Red Maple example, rubrum is the species name. Often species names are derived from descriptive terms; “rubrum” is Latin for red.
The scientific name not only uniquely describes a specific plant species, but it aids in understanding how different plant species are related. Acer rubrum (Red Maple) is a different plant than Acer circinatum (Vine Maple), but both are members of the Acer, or Maple, genus.
There are four common ways that scientific names are written:
- The entire scientific name is italicized, with the first letter of the genus capitalized and the species name in lowercase. An example is Acer rubrum.
- The entire scientific name is underlined, also with the first letter of the genus name capitalized and the species name in lowercase. An example is Acer rubrum.
- If you are discussing a list of species that all belong to the same genus, the genus name can be abbreviated in the later names. For example, two members of the Maple genus are Acer rubrum and A. circinatum.
- If one is talking about several species that belong to a single genus, the spp. abbreviation may be used after the genus name to indicate multiple species within that genus. For example, Acer rubrum and A. circinatum are two of the many Acer spp.
Variations on the Scientific Name
While reading plant literature or browsing nursery catalogs, one may come across some variations in plant scientific names. These are often seen when talking about varieties, hybrids, and cultivars.
Plant varieties are members of the same plant species that have a specific set of characteristics that can usually be passed on to the next generation through natural reproduction. A variety is a subordinate group, or subset, of a specific species.
In horticultural literature, a variety is indicated by the “var.” abbreviation. For example, the scientific name for honeylocust is Gleditsia triacanthos, where the scientific name for the thornless variety of honeylocust is Gleditsia triacanthos var. inermis.
Hybrids are a cross between different species. The parent plants are usually within the same genus. (There are special rules for naming naturally-occurring hybrids of indeterminate parentage, and those hybrids which are crosses between plants in different genera.)
The multiplication sign “x” is used to indicate that the plant is a hybrid, with the multiplication sign placed between the common parent genus name and the hybrid’s unique species name. Fragaria x ananassa is the scientific name for commercial strawberries, a cross between Fragaria chiloensis and F. virginiana.
The word cultivar is an abbreviation of the term “cultivated variety”. Cultivars are plants of a single species which have been selectively bred for a specific characteristic, such as greater yield, larger blooms, color variation, more compact growth, or the like. Many cultivars are propagated asexually so that the desirable characteristics are not lost in future generations. Bear in mind that many cultivars are either patented or trademarked, and can not be propagated or sold without permission.
The cultivar name is written in plain text (not italicized) within single quotation marks, and is found behind the scientific name of the source species. For example,Veronica umbrosa ‘Georgia Blue’ is the scientific name of the Georgia Blue cultivar of the creeping groundcover Veronica umbrosa.
Scientific Plant Names. Oregon State University. Discusses scientific plant names.
The Meaning of Botanical Names. WSU Extension Spokane County. Fact sheet contains a list of words that are frequently used in the naming of plants.
USDA Plants Database. The PLANTS Database provides standardized information about the vascular plants, mosses, liverworts, hornworts, and lichens of the U.S. and its territories.
International Code of Botanical Nomenclature (Saint Louis Code, 2001). International Botanical Congress. The electronic version of the rules that govern scientific naming in botany, including phycology and mycology.
Plant Pronunciation Guide. Rainy Side Gardeners. A guide to help you pronounce botanical names.