• Share

PRINT

Most plants have common names. However, these can be inexact. For example, is a “snowball bush” a viburnum or a hydrangea?

The plant kingdom contains about 300,000 species. In the 1700s, Carl Linnaeus devised a method to classify and name them. The method of identification and classification (taxonomy) is the basis for plant names (nomenclature).

You might say, “That’s Greek to me.” But actually, a plant’s scientific name is often in Latin. On a plant tag, you will typically find a two-part name (binomial) that identifies the plant species.

The first name is the genus name; plants in a plant family that share common characteristics are placed in a genus. The second part of the species name is a specific epithet, which describes a plant characteristic such as color (e.g., alba means white) or growth habit (e.g., sylvatica means growing in the woods); the location where it was found (e.g., japonica for Japan); or the person who discovered it or who is being honored (e.g., engelmannii for Engelmann).

In some cases, the plant is described further by variety, cultivar, hybrid or authority designations.

The variety is a naturally occurring variation from the straight species, often considered a mutation. For example, a redbud tree typically sports pink flowers; however, a white-flowering redbud variety occurring in nature is identified by “alba.” Seeds from this variety would produce white-flowering redbud trees.

Cultivar means a purposely bred and propagated plant (by humans) for specific desirable characteristics. The cultivar name follows the variety name. (Note: Plants grown from the seeds of a cultivar typically would not look like the parent. For a cloned offspring of a cultivar, the plant often must be grown from cuttings, grafting, or tissue cultures.) A plant can be both a variety and a cultivar.

A hybrid is a cross between two varieties or species. The authority is the first person who described the species.

Write it right

Writing plant names has its own rules. They are written in the following order:

Genus begins with a capital letter and is italicized. It is considered a noun.

The specific epithet is lowercase and italicized. Because it is a descriptor or an adjective, it is never used without the genus name preceding it.

A variety is denoted with “var.” followed by the name in lowercase and italics.

A cultivar begins with a capital letter and in placed within single quotation marks.

A hybrid is identified by placing an “x” before the specific epithet, which is italicized.

The authority follows the species name and is usually abbreviated. For example, “L.” stands for Carl Linnaeus.

Here’s an example for what you might call “black-eyed Susan” — Rudbeckia fulgida var. sullivantii ‘Goldsturm’

Rudbeckia fulgida is a Missouri native plant. The genus name honors Olof Rudbeck (1630-1702), a Swedish botanist. The specific epithet means shining or glistening.

Var. sullivantii, commonly called Sullivant’s coneflower, is native to swamps and meadows from Arkansas to the east coast. ‘Goldsturm,’ introduced in 1937, is a slightly more compact plant with larger and brighter flowers than the species or variety. It won the 1999 Perennial Plant of the Year award, and is one of the most popular garden perennials in cultivation.

Peter Piper picked a pepper

So how do these plant names help you? They may help you pick the right pepper plant! Bell pepper and chili or hot pepper belong to the genus Capsicum; however, black pepper is the common plant name for Piper nigrum.

Awareness of related plants can be important too. For example, it might be helpful to know that the groundcover pachysandra is in the boxwood family (Buxaceae); therefore, both pachysandra and boxwood are susceptible to the fungus that causes boxwood blight. On a more positive note, trees and shrubs in the Acer genus are known for brilliant fall color.

Additionally, you might discover that some plant varieties grow taller than others; some cultivars have been developed for disease resistance; some hybrids tolerate heat better than the straight species.

If you’re looking for a specific plant, make sure you know the scientific name (species and variety and/or cultivar) before going to the garden center.

Lela Martin is a Master Gardener with the Chesterfield County office of the Virginia Cooperative Extension