Carnations And Pinks
Plants need names that identify them and link them to others in the same family. The Greeks and Romans originated the system of naming plants by including descriptive details in their title, but it was Carl Linnaeus, a Swedish botanist in the 18th century, who devised the less cumbersome classification system still used today. Instead of the descriptive phrases used by herbalists and botanists of his day, Linnaeus gave each plant two names in Latin form. The first is the word for the genus-equivalent to our surname-and the second is a specific description, such as our given name. Together they provide a name by which this particular plant species is universally known. The entire plant kingdom is divided and subdivided into a multibranched "family tree," according to each plant's characteristics. As new discoveries are made, or more precise analyses become possible, botanists sometimes rename plants or reclassify their family connections. The broadest grouping to which a plant belongs is the family, similar to a human clan, and this is determined by the structure of the flowers, the fruits and other parts of the plant. So the genus Dianthus belongs to the larger family of Caryophyllaceae and includes the tall-stemmed, highly bred, many-petaled carnations, as well as the sweet-smelling pinks. Within any plant family there may be one genus or many, and Lychnis, Silene and Gypsophila are genera, related to Dianthus, also belonging to Caryophyllaceae. Within each genus there may be one or many species. Carnation or pink, all those we know today have been bred from various species of Dianthus that originated in central and southern Europe and Asia. Carnations, it is thought, are descended from the species Dianthus caryophyllus and have 30 chromosomes; pinks are derived from the species D. plumarius and, curiously, though they appear less complicated, have 90 chromosomes. An individual plant may be a variety, which, strictly speaking, occurs naturally and is defined by botanists as a taxon below species level. Alternatively, it may be a cultivar, which is a variant resulting from human activity. Species will come true to type from seed
; cultivars must be propagated by cuttings or other vegetative means to retain their genetic structure. Dianthus caryophyllus carries the genes for the characteristic clove scent of the traditional carnation. It also brings to the genus tall, upright growth; thick, strong flower stems with long spaces between the joints or nodes; and often double flowers, usually bigger than those of pinks and in almost every color except blue. These are the attributes that have been so important for the carnation as a cut flower. Among the genus Dianthus are five main types: Border carnations
have a long ancestry in Europe. They are hardy (though short-lived) perennials that will survive where temperatures sometimes plummet to -40�F. Annual carnations
are popular throughout North America. They flower prolifically right through summer, with blooms generally smaller than those of the border carnations, and although they will overwinter in mild climates, they are usually treated as annuals and planted from seed each year. Perpetual-flowering carnations
, those we buy from florists, made their appearance more recently. They first came on the market around 1850 and were bred to produce blooms for the cut-flower trade. These carnations are raised mainly by commercial growers and, in greenhouses where they usually grow, they will continue flowering all winter provided the temperature falls no lower than 50�F. Pinks
are well-loved garden plants, widely grown and cherished for their dainty flowers, often delicious perfume and their attractive blue-gray foliage that usually forms a low-growing, neat clump. The stems of pinks are thinner and shorter than those of carnations; the flowers may be single or double, fringed or rounded and they come in every color except blue and yellow. Sweet Williams
, vivid and summer-flowering, are also part of the Dianthus family. Dwarf or taller-growing varieties all bear dense clusters of brilliantly colored blooms on stout stems. When sweet Williams are in full flower, the bright green leaves become almost obscured. The name of the genus was derived from two Greek words-Dios, meaning divine, and anthos, flower. It is believed that Theophrastus, a pupil of Aristotle, in about 300 BC dedicated the flowers to Zeus, the most powerful deity in the line-up of Greek gods, but the early history of Dianthus is uncertain and the first steps in their evolution unknown. Linnaeus was the first to describe the genus, in 1753. By 1893 more than 230 species had been described, but of this number very few are of any importance to gardeners.