From Seed to Seed:
Plant Science for K-8 Educators

Digging Deeper

Varieties

Sometimes a population of plants within a species differs from other members of the species in some significant way-for example, a population may have white flowers instead of the usual blue flowers. This unique population is given a variety name-added in italics after the species name-to distinguish it from other members of the species.

Hollyhock: Alcea rosea

Black-flowered hollyhock: Alcea rosea var. nigra

Eastern flowering dogwood: Cornus florida
Eastern flowering dogwood with red bracts: Cornus florida var. rubra

You may see the name written without the abbreviation "var." inserted, but technically this should be included. The term "subspecies" is also used to describe a subgroup of a species. Usually the word subspecies is used to describe a natural population, and often the term describes plants with a particular geographical distribution or ecological range.

Cultivars. If a variety is created through cultivation-that is, it doesn't occur as a natural population, but is the result of breeding efforts by horticulturists-then it is called a cultivar (short for cultivated variety). A cultivar is distinguished from a naturally occurring variety by capitalizing the cultivar name and placing it in single quotes in plain type.

Tall summer phlox: Phlox paniculata
A named cultivar of tall summer phlox: Phlox paniculata 'Blue Boy'

A named cultivar of Eastern flowering dogwood: Cornus florida 'Bay Beauty'

Another way to indicate a cultivar is with the abbreviation cv. instead of the single quotes-for example, Cornus florida cv. Bay Beauty.

Hybrids. Hybrids are the result of sexual reproduction between different species. Hybrid plants can occur naturally, but most of the hybrids familiar to gardeners are the result of breeding work.

Phlox x procumbens is a hybrid resulting from a cross between P. stolonifera (creeping phlox) and P. subulata (moss phlox).

Phlox x procumbens 'Variegata' is a hybrid cultivar with variegated foliage.