One of the reasons that American trees and shrubs were so desired in England in the 1730s was that British gardeners believed that plants from America could be grown in the open rather than in hothouses. Interest in acquiring new plants became an exciting obsession for several enterprising gentlemen gardeners in England.
In 1736, news of the acquisition of rare plants from America reached the young Swedish botanist, Carl von Linne - more commonly known by his pen name Linnaeus. He decided it was necessary to travel to England to meet all the important gardeners and botanists there and to see these rare plants for himself. Only seven months before his trip, he had published "Systema Naturae," the book in which he proposed a whole new system of classifying plants based on their reproductive organs. He divided flowering plants into 23 classes, according to the number of their stamens (male organs), which he called "husbands" and by the number of pistils (female organs) or "wives." Many of the English botanists he encountered were scandalized to think that plants made love in the flower head - the "bridal bed." One was quoted as saying that Linnaeus' method was "too smutty for British ears." Interestingly, Lineaeus' ideas were welcomed in America.
In 1753, Linnaeus published "Species Plantarum," which became the most important botanical treatise of the 18th century. This publication is the universally acknowledged starting point of modern plant names. He proposed changing the earlier cumbersome system of naming plants using 12 to 20 descriptive words to a scientific latinized two-word name, a first name and a surname, the plant's genus and species names.
The custom of using latinized names and spelling originated from medieval scholarship. According to his binomial system of horticultural nomenclature, plants with many recognizable botanical features in common are grouped into plant families such as Rosaceae, Orchidaceae, Pinaceae, etc. The Latin ending "aceae" means belonging to, e.g., Rosaceae indicates plants within this classification belong to the rose family.
Within each plant family are various genera (plural of genus). A genus is a group of plants having common characteristics of sufficient importance and in sufficient quantity to warrant their classification by a single name. The generic name, or genus, functions for a plant as the surname serves a person. The specific name, or species, is equivalent to a given name for an individual. The "surname" or the genus, e.g., Magnolia, often commemorates a friend or the botanist who discovered the genus.
The second word, also referred to as the specific epithet is typically a descriptive term, e.g., grandiflora (large-flowered), is added to signify the individual species within a genus. By convention, the Latin binomial name is italicized or underlined; the genus is capitalized; the specific epithet is usually not capitalized. The letter "L" after a plant name indicates that Linnaeus invented or validated the name.
The most popular group of plants in the world is Rosaceae, the rose family. This is a large family of flowering plants with about 3,350 species in 122 genera. Several ornamental trees and shrubs (e.g., roses, photinia, pyracantha) and edible fruits (apples, cherries, peaches, pears, raspberries and strawberries) and almonds are included in this family. To illustrate Lineaeus' naming system, the binomial name for the native California rose is written as follows: Rosa californica or Rosa californica.
With the publication of his system of binomial nomenclature, Linnaeus' stature in the botanical world of the 18th century rose. His position of power enabled him to rename plants in honor or in memory of fellow botanists. He named the Magnolia after Peter Magnol (1638 to 1715), a professor of botany and director of the Royal Botanic Garden in Montpelier, France, who introduced the concept of plant families.
On another occasion, to get revenge on a fellow botanist who criticized his naming system, he picked out an ugly, stinking weed that grows in wastelands and named it Siegesbeckia after Johann Siegebeck.
Plant taxonomy is the science that finds, describes, classifies, identifies and names plants. While Linnaeus' naming system relied totally on a plant's reproductive organs, today's botanists analyze the DNA and the morphology of plants together with the known evolutionary history to determine relationships between plants. Taxonomy results in an organized system for the naming and cataloging of future specimens, and ideally reflects scientific ideas about plant inter-relationships.
Referring to plants by their common name can be confusing, as a single common name can denote various plants in different parts of the country or even the world. The same common name can be used for several plants that not only look different but vary greatly in growth habit, needs and bloom season.
Advances in botanical knowledge can lead to a plant being re-named or reclassified. For instance, several species formerly included in the genus Helichrysum were transferred to the new genus Bracteantha in 1991.
However, in 2001, it was noted that the name Xerochrysum, published by a Russian botanist in 1990, should take precedence under the rules of botanical nomenclature. This means that Bracteantha bracteatum (common names: strawflower, everlasting daisy or golden everlasting) is now reclassified under the genus Xerochrysum.
In an era of intensive plant breeding and marketing, international trade and high consumer interest in gardening, taxonomic name changes result in a state of confusion for home gardeners, landscape contractors, nurserymen and botanical gardens.
So, be sure to read the plant label when you go to the nursery on a buying spree. The label provides both the latinized binomial name and the common name (and the specific cultivar, if appropriate) along with a description. Be sure to note the helpful information about how and under what circumstances the plant will thrive; it's important reading.
The University of California Marin Master Gardeners are sponsored by UC Cooperative Extension. For questions about gardening, plant pests or diseases, call 499-4204 from 9 a.m. to noon, and 1 to 4 p.m. weekdays, or bring in samples or pictures to 1682 Novato Blvd., Suite 150B, Novato.