How Plants Are Classified

Most plants, though not all, have a name in the language of every country in which they occur naturally. In many cases they also have several local names. In addition, every plant known to science has an “official” or scientific name. This name is in Latin, by convention it is written in italic characters, and it has two parts. The first, written with an initial capital letter, is the name of the genus, and the second, with an initial lowercase letter, is the name of the species. Subspecies are given an italicized name following the specific name. With some plants there is more than one variety of a species or subspecies, generating an additional italicized name preceded by the abbreviation “var.” for “variety.”

Scientific plant names are devised according to a set of rules contained in the International Code of Botanical Nomenclature. The person proposing a name must submit it, together with an explanation of the name and a specimen of the plant (usually a herbarium specimen), to the International Committee on Botanical Nomenclature, which is the body that administers the code. If the committee accepts the name, the person who devised it may be identified by initials following the full name. For example, the common daisy, which was named by Linnaeus, is Bellis perennis L., and the California redwood is Sequoia sempervirens D. Don, for David Don (1799 or 1800–1841).

Higher taxonomic categories exist above the level of genus. Genera are grouped into families, families into orders, orders into classes, and classes into phyla. Above the level of phylum, all plants belong to the kingdom Plantae, and the Plantae belongs to the domain Eukarya. The full classification of Bellis perennis is as follows:

Domain Eukarya (or Eucarya) (Organisms with eukaryotic cells)
Kingdom Plantae (or Metaphyta) (All plants)
Phylum (or division) Anthophyta (flowering plants)
Class Eudicots (dicotyledons)
Order Asterales (plants related to sunflowers)
Family Asteraceae (sunflower family)
Genus Bellis
Species perennis
Name Bellis perennis L.

Where necessary, taxonomists add intermediate ranks between the main ranks, such as subkingdom, subphylum, superphylum, subclass, superclass, suborder, superorder, subfamily, superfamily, and subspecies.