Plant Kingdom

Plant Kingdom
Bryophytes: Small with leaflike, stemlike, and rootlike structures.
which are Disseminated by spores: mosses, liverworts, hornworts.
Tracheophytes: Larger with true leaves, stems, and roots.
Seedless: Ferns, horsetails, club mosses.
Seed Plants:
Gymnosperms: Usually have cones, no flowers, seeds not enclosed in fruit: pines, spruces, firs, hemlocks, cycads, ginkgo.
Angiosperms: Have flowers, seeds enclosed in fruit
Monocotyledons: Leaves have parallel veins, one seed leaf: grasses, orchids, lilies, palms.
Dicotyledons: Leaves have netted veins, two seed leaves: cherry trees, maples, coffee, daisies, etc.
This informal way of describing plant classification gives an overview of how plants are classified. Botanists use a more complex system. A botanist divides the plant kingdom into Divisions, similar to the Phyla used to divide the animal kingdom. There are twelve divisions. Referring to the above ranking, three of these divisions are Bryophytes, four are seedless plants, four are Gymnosperms, and one is Angiosperms. Each Division is further divided into Classes, which are divided into Orders, which are divided into Families, which are divided into Genera (singular, Genus), which are divided into species, which is the "basic unit" of classification. Put somewhat simply, individuals in a species are able to breed with each other, while in broader categories individuals do not interbreed.
THE BINOMIAL SYSTEM OF CLASSIFICATION
The foxglove plant is the source of digitalis.Photo by Steven R. King, 1996.The scientific or botanical name of a plant is the means by which we give it its unique place in the scientific and biological world. Begun by Carolus Linneaus, a Swedish botanist, in the eighteenth century, this name is binomial (has two parts), consisting of genus and species, both of which are expressed in Latin. The genus or generic name is a noun which usually names some aspect of a plant, such as Coffea, the Latinized form of the Arabic word for beverage, kahwah. The species or specific name is usually an adjective that describes the genus. In the case of coffee, the species is arabica, indicating that the plant was thought to originate in Arabia. The coffee plant botanical name, Coffea arabica, refers to only one plant and cannot be confused with any other. Its botanical name is unique to that particular plant the world over.
The botanical name is often followed by a letter or letters which stand for the botanist who named that plant. The coffee plant's complete botanical name is Coffea arabica L., the L. standing for Linneaus. If the original botanical name of a plant is later changed, the original classifier is still noted in parentheses. Other often used abbreviations are Sarg. for Charles Sprague Sargent, founder of Harvard University's Arnold Arboretum; Lam. for Jean Baptiste Lamarck, French evolutionist and botanist; and Audub. for John James Audubon, ornithologist, naturalist, and painter. (Interestingly, this convention of naming the discoverer is not found in the naming of animals.) Sometimes the Family name is included, which groups the genera. It can usually be distinguished by its ending--"eae."
Linneaus's book Species Plantarum (The Species of Plants), published in 1753, continues to influence the naming of plants today. It is the starting point for checking whether a name has been used previously to insure that each plant is given a unique name. The earliest name for a plant is usually the official name should a dispute arise.