What is a genus?

A genus is a group of organisms, in this case trees, that are closely related and share similar characteristics. For example, all trees in the Pine genus (Pinus) have long, narrow needles bound in bundles and hard, woody cones with thick, tough scales.

All plants have two types of names: a common name and a scientific name. Common names are written in English (or in German if you're in Germany, or in French if you're in France), but scientific names are always written in Latin, so they can be used anywhere in the world.

Example:

• Common name = sugar pine
• Scientific name = Pinus lambertiana

The genus name refers to the general type of tree (e.g. "pine" or Pinus), while the species name refers to the specific type of pine (e.g. "sugar" or lambertiana).

Other pines have the same genus name in both English and Latin, but they have different species names.

For example:

• ponderosa pine: Pinus ponderosa
• lodgepole pine: Pinus contorta

"Genera" is the plural term for more than one genus.

Scientific names are always italicized or underlined.

Although the naming system takes a while to get used to, you'll soon realize that learning tree names can be fun. They often tell you something special about the tree--such as who discovered it, a particular growth characteristic, or where it grows. When you encounter a new plant, see what you can learn from its name.