Genus is a cluster of plants with common characteristics that are easily recognized. Species is a group of plants that can generally interbreed only among themselves. They show persistent differences from members of closely related species. A good example of binomial nomenclature can be seen in maple trees. Properly written scientific names are underlined or italicized.
Binomial nomenclature gives many descriptive clues about the plant.
It can indicate color, form, who discovered it or where it originated. It is worthwhile for the home gardener to become familiar with this binomial nomenclature because many excellent gardening magazines and reference books will refer to plants by their scientific names. Plants also are grouped together within a species. A variety is a group of plants that developed a new characteristic through naturally occurring hybridization. Cultivars or cultivated varieties are new or hybrid plants that are hybridized by human manipulation.