UNITED STATES—Nomenclature is a standardized technology of naming. It dictates the universal ‘botanical’ names of all plants, so that everyone everywhere can communicate more efficiently about horticulture. Botanical names might seem confusing, and maybe even unflattering, but they eliminate the confusion associated with regional common names that are as variable as languages and cultures.

For example, the white pine from Northern California is not the same as the white pine from Maine, even though they both have the same common name. However, Pinus monticola, the white pine from Northern California, is the same everywhere, even if grown in Maine. This particular botanical name is only for this particular white pine, so eliminates confusion with other white pines.

Botanical names are also known as ‘Latin’ names because they are (obviously) Latin. The first name is the more general part of the name, so is known as the ‘genus’ (or ‘genera’ in plural). The second name is the more specific part of the name, so is known as the ‘species’ (or ‘specie’ in plural). The genus name should be capitalized; but the species name is not. Both are italicized.

Acer is the genus of all maples. Salix is the genus of all willows. These names identify particular genera, but are no more specific alone. Acer rubrum more specifically identifies a popular North American maple that is known locally as red maple. Salix babylonica specifically identifies a common willow known locally as weeping willow. This is almost as specific as nomenclature gets.

A few specie have varieties or cultivars (cultivated varieties) which are variants of the basic species. Variety or cultivar names are added after specie names. They are capitalized, unitalicized and semi-quoted. For example, Acer rubrum ‘October Glory’ is the October Glory red maple. Olea europaea ‘Little Ollie’ is a fruitless, dense and short cultivar of the familiar European olive tree.

Nomenclature of plants is similar to nomenclature of cars. Buick, Chrysler and Mercury are genera of cars. Electra, Imperial and Grand Marquis are specie of Buick, Chrysler and Mercury, respectively. ‘Limited,’ ‘Custom’ and ‘Brougham’ are their cultivars. There are of course many more plants with bigger and stranger names, but the system for identification works the same way.

Highlight: Little Ollie olive

Those of us who appreciate olive trees for their fruit production or distinctively gnarly trunks probably would not understand the popularity of the Little Ollie olive, Olea europaea ‘Little Ollie.’ Not only is it completely fruitless, but it lacks sculptural trunks and limbs. It is instead a short and and shrubby plant that gets only about three or four feet tall, with very dense grayish green foliage. Only the narrow evergreen leaves are recognizable as those of an olive tree.

Little Ollie olive behaves something like boxwood, and does not grow much faster. It can even be shorn as a hedge or topiary. It is quite resilient to heat and harsh exposure, and once established, it does not need much water. Because it is so compact, and has such resilient roots, it is popularly grown in large urns or planters. The grayish foliage is a nice backdrop for more colorful annuals and flowering perennials.