Classifying Trees

Common Names

Many plants and animals have common names as well as scientific names. Common names provide a general description of the organism. Most people understand what is meant by rose, dogwood, or ragweed. However, common names are often not specific enough for identification of the species. For example, there are several kinds of dogwood trees. The specific kind of dogwood is not specified by the simple common name for this plant.

Why Use Scientific Names?

Common names can be misleading and make it difficult for people from different cultures and different parts of the world to communicate. For example,

  • Australian pine, a non-native tree used as an ornamental in Florida is not even a cone-bearing plant. It is a flowering plant in the Cassurinaceae (family), not the Pinaceae (the pine family, to which the familiar pines such as white pine, red pine, sand pine, fir, and hemlock, belong).
  • A more familiar example is the common use of the term 'cedar', which is applied to eastern red cedar (Juniperus virginiana), northern white cedar (Thuja occidentalis), and sometimes even bald cypress (Taxodium distichum). All are in the Cupressaceae and are distinct genera, yet the use of the term 'cedar' is not precise.

Scientific names describe both the plants' distinguishing characteristics and the relationships among organisms.

Living organisms are classified hierarchically (in ranked categories). Starting with the most basic and least inclusive level, species are typically defined as organisms that are able to interbreed and produce recognizably similar offspring. Similar species are grouped into a genus; genera sharing distinguishing characteristics are grouped into families, and families into orders, classes, and so on.

For the purposes of this Web module, the levels of

FAMILY (e.g. Pinaceae, Juglandaceae - the pine and walnut families, respectively)
GENUS (Plural = genera. e.g. - Pinus for pine, and Quercus for oak)
SPECIES (e.g. Pinus strobus for white pine, and Quercus alba for white oak)

Other things to note:

The genus and family names are always capitalized.
Families end in the suffix ‘-aceae.’
Both genus and species are underlined or shown in italics.
Higher taxonomic levels include:

Order (e.g. Pinales),
Class (e.g. Pinopsida),
Division (e.g. Pinophyta), and
Kingdom (e.g. Plantae)