Scientific Plant Names, Oregon State Univ., LANDSCAPE PLANTS
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Scientific Plant Names
������      The current system of using Latin to name biological organisms was  developed by Carl von Linne, more commonly known by his pen name Linnaeus,  about 250 years ago.  (His Species Plantarum was published in 1753.)  This system  is known as the Linnaean binomial system of nomenclature.  In this system, biological organisms, such as plants, are given two latinized names, the Latin binomial or so-called "scientific name".  The first name represents the
and the second name is termed the
specific epithet.
The generic name in combination with the specific epithet constitutes the species name.  Thus each species has a two part name or binomial.   The custom of using latinized names and spelling originated from medieval scholarship and the use of Latin in most botanical publications until the middle of the nineteenth century.
      In this binomial system, humans are known taxonomically as:
Homo sapiens
(Latin: homo, man; sapiens, wise or knowing; hence, "wise man" or "knowing man")
The tree species that is commonly known in North America as red maple has been given the Latin binomial of Acer rubrum.
Red Maple   =   Acer rubrum
The red maple is in the "maple" genus, which is called Acer, and its specific epithet is rubrum, which is Latin for red.  Therefore, the binomial name for this species is Acer rubrum.   Of course plants are named with reference to more or less similar  plants, for example other Acer, and in doing so are placed into a number of increasingly  broader taxonomic ranks or taxa (singular, taxon).  An example is shown below:
 Kingdom   
     Magnoliophyta -- angiosperms, flowering plants   (~259,000)
      Class
       Rosidae -- flowers with separate petals   (~58,000)
        Order
        Sapindales -- woody, lobed or compound leaves   (~5,700)
         Family
         Aceraceae -- (now Sapindaceae)  opposite leaves, winged samara; mostly maples   (~152)
         Genus
          Species
          Acer rubrum L. -- red maple   (1)
      You might argue that we should just use the so-called "common names" of plants, since it would be much simpler, especially since few people can read or speak   Latin.  Thus we could all agree that the name for red maple is Red Maple, this would be an English   binomial system.  However, there are problems with using common names, such as:
"Common names" are often common only to a localized region.  The Red Maple is commonly called the Scarlet or Swamp Maple in some areas.  The tree Nyssa sylvatica, which is native to the eastern US, has at least four common names (i.e., Sour Gum, Black Gum, Black Tupelo, Pepperidge).  In England the white waterlily has 15 common names, and if you include the common German, French, and Dutch names it has over 240 names!
Sometimes the same common name is used in different regions to identify completely different plants.  A plant in Georgia called ironweed is of the genus Sidai, whereas in the Midwest ironweed refers to a plant in the genus Vernonia.
Common names usually do not provide information on generic or family relationships, they tend to be independent of other names.  In fact common names may suggest erroneous relationships between plants.  For example, only one of the following plants is a "true cedar", i.e., of the genus Cedrus:  Japanese Cedar (Cryptomeria japonica), Port Orford Cedar (Chamaecyparis lawsoniana), Western Red Cedar (Thuja plicata), Eastern Red Cedar (Juniperus virginiana), and Deodar Cedar (Cedrus deodara).
Some plants, especially those that are rare, do not have common names.   Or more correctly, they lack common names in English, most may have been named by native people  familiar with a given plant.
Since we now frequently interact with people all over the globe, using a myriad of languages, a single, agreed upon name for an organism is a great advantage.  Thus the success of the Linnaean binomial system.
      A Latin binomial name (the "scientific name") is italicized or underlined, the genus is capitalized and the specific epithet is usually not capitalized.  However, the specific epithet may be capitalized if it is,
derived from a person's name (e.g., Spiraea douglasii or Spiraea Douglasii - after David Douglas), or
from a vernacular name (e.g., Picea omorika or Picea Omorika - the Balkan name for spruce), or
from a generic name (e.g., Picea abies or Picea Abies - where Abies is the genus name of Fir).
The tree commonly known as Sugar Maple, has the scientific name Acer saccharum, but is should be written as:
Acer saccharum    or   Acer saccharum,
However, sometime you might see it written as:
Acer saccharum Marsh.   or   Acer saccharum Marsh.
The abbreviated name following the plant name (i.e., Marsh.) is the name of the "authority" or "author", the individual who first named the plant "scientifically", in this case Humphrey Marshall.  Similarly, the scientific name of the white oak is written as
Quercus alba L.
here the the letter "L" is used to identify Linnaeus as the authority.  In most nursery and landscaping literature the authority name does not accompany the scientific name.
Hybrids
      Sometimes it is possible to obtain offspring or progeny from  crossing plants of different species, for example say two species of Maple (Acer).   Frequently a  ×  (the multiplication sign) is used in a scientific name of  such hybrid plants.   The strawberry of commerce is a hybrid, the result of a chance cross between plants of two strawberry (Fragaria) species, Fragaria chiloensis and Fragaria virginiana.  The scientific name of the commercial strawberry is,
Fragaria × ananassa,
with the  ×   indicating that it is a hybrid.  (The proper designation is Fragaria ×ananassa, with no space between the × and the specific epithet, however, this sometimes causes confusion since the  ×   may be read as the letter "x".)   Occasionally plants in different genera have been hybridized, resulting in a intergeneric hybrid.  For example, English Ivy (Hedera helix) was successfully crossed with Japanese Fatsia (Fatsia japonica), and the resulting plant has the common name Fatshedera; its botanical name is
��  The  ×  before the genus name indicates that this plant is a hybrid of two genera.
Pronunciation
������      In his book, Botanical Latin, William Stearn, stated the following: "Botanical Latin is  essentially a written language, but the scientific names of plants often occur in  speech. How they are pronounced really matters little provided they sound pleasant and are  understandable by all concerned.  This is most likely to be attained by pronouncing  them in accordance with the rules of classical Latin pronunciation.  There are, however, several systems,  since people tend to pronounce Latin words by analogy with words of their own language" (p. 53).
      An example of this difference is shown in two "authoritatve" pronunciations  of Acer saccharinum, the Silver Maple:
A-ser sak-kar-I-num (American)        AY-ser sak-a-REE-num  (British)
and  for the David Maple, Acer davidii:
A-ser da-VID-ee-I (American)        AY-ser da-VID-ee-ee  (British)
������      For more information on this topic, please refer to one of Stearn's books or to an article in the magazine, Horticulture (Fisher, 2000).
Some Terms
Genus:
Weakly defined as a more or less closely related and definable group of organisms (plants) comprising  one or more species.  A genus is an aggregate of closely related species.
The species have more characteristics in common with each other than they do with species of other genera  in the same family.  Similarity of flowers and fruits is the most widely used feature of comparison.
A genus may contain a single species (e.g., Ginkgo) or more than 100 (e.g., Rosa).
Species:
This is difficult to define, more a concept than an absolute entity.  Sometimes defined  as a group of individual organisms (plants) that are fundamentally alike.
Ideally a species should be separated by distinct morphological differences from other closely related  species.  This is necessary for a practical classification that can be used by others.
All the individuals in a given species are not identical.  Think of it as a  population in which any character might be expressed to different degrees in each individual.  Humans are classified as the single species Homo sapiens, but we certainly are not morphologically identical.  Check this idea out by taking a stroll in the woods and examine plants of a single species.
Species is abbreviated sp. (singular) or spp. (plural).
Variety (Latin, varietas):
In the botanical sense, variety is a population of plants of a species that display marked differences in nature, and these differences are transmitted by seed (i.e., inherited).
Variety, abbreviated var. is subordinate to species. A variety name is written in lower case, italicized or underlined, and is preceded by the abbreviation var.  For example, the common honeylocust in the wild has thorns, but thornless plants are also found.  The honeylocust is