For your reference, some terms related to plant names are defined below.
This page is a work in progress, and definitions may be updated periodically. Please don’t hesitate to contact us with corrections or if you have anything to add.
➤Common name This is a name commonly used to identify a plant. Rose, broccoli, and weeping willow are all common names. Common names can often be memorable, poetic, and pleasant-sounding, but they are not always universal or unique to a particular plant. Any number of related or unrelated plants can have the same common name. Also, a single plant can have many common names, in multiple languages, which may cause confusion.
For example, plants in both the Capsicum and Piper genera have the common name pepper. If someone wants to learn about the seeds of a Piper species and uses the internet to look up this information, entering the common name “pepper” in the search box, then the search engine will not know which plant is meant, and may return results for a Capsicum species instead.
➤Scientific name (binomial name) Every plant has a scientific name or binomial name (or binomial) that is universal and unique to that plant. Each word in this two-part name is given a Latin suffix. The first part of the name identifies the plant’s genus, while the second part identifies its species. Scientific names are italicized or underlined, with the genus name capitalized and the species name, or specific epithet, written in lowercase.
For example, the binomial name of the common bean plant is Phaseolus vulgaris.
➤Variety or cultivar name Often it is necessary to identify a plant even more precisely, by its variety or cultivar name. Seed savers should be aware of a plant’s variety or cultivar name when possible, because the plants from which they are saving seeds are often distinguished from one another at this level.
A variety name is a name given to a plant that has mutated from the species norm in some way. A variety has a unique appearance but will cross-pollinate with other members of the species. “Varieties often occur in nature and most varieties are true to type. That means the seedlings grown from a variety will also have the same unique characteristic of the parent plant.” (1) Variety names are tacked on to the end of binomials, usually following the abbreviation “var.” The first two words of the binomial are italicized or underlined, while the third word is not.
For example, wild cabbage is Brassica oleracea var. oleracea. Head-forming cabbage, a descendent of wild cabbage, is Brassica oleracea var. capitata. Collards and kale are Brassica oleracea var. acephala. Broccoli and cauliflower are Brassica oleracea var. botrytis. The Brussels sprouts plant is Brassica oleracea var. gemmifera.
In the case of domesticated plants that have developed new characteristics due to human selection and cultivation, a cultivar— or cultivated variety– name is used. Cultivar names are capitalized and are generally placed in single quotation marks, following a plant’s binomial name, or following its variety name, if applicable. A plant can have both a variety and a cultivar name. (See the cabbage cultivar example below.) Cultivar names are not italicized or underlined.
For example, the cultivar name of the ‘Tavera’ bush bean is Phaseolus vulgaris ‘Tavera’. One cabbage cultivar is Brassica oleracea var. capitata ‘Golden Acre.’
***Please note, the terms variety and cultivar are often used imprecisely and interchangeably. Their definitions will depend on usage. “In today’s world of horticulture, cultivars are planted and used more than varieties. Yet we often still refer to a type of plant species as a variety instead of what is actually is a cultivar.” (1) Here we often use the terms casually and interchangeably, reflecting common usage.
(1) “Cultivar versus Variety.” Haynes, Cindy – Department of Horticulture, Iowa State University. Horticulture & Home Pest News. Issue IC-499(2), February 6, 2008. Iowa State University Extension and Outreach.
Category: Plant taxonomy (Wikipedia collection of articles)