At the simplest level of scientific classification, each plant has a name made up of two parts, a generic (or genus) name and a specific name or epithet. Together, these two names are referred to as a binomial.
A generic name is a ‘collective name’ for a group of plants. It indicates a grouping of organisms that all share a suite of similar characters. Ideally these should all have evolved from one common ancestor. The specific name, allows us to distinguish between different organisms within a genus.
Binomial names are always written with the generic name first, starting with a capital letter, e.g.: Grevillea
The specific epithet always follows the generic name, starting with a lower-case letter, e.g.: victoriae
The full species name or binomial being Grevillea victoriae.
Generic and specific names are generally in Latin or are Latinised words from other languages, particularly Greek. Other derivations are also sometimes used, such as Aboriginal names or even acronyms. Specific epithets also need to conform to certain grammatical rules depending on the form of the generic name.
There are hierarchical levels of classification (ranks) above and below the genus and species, the most commonly referred to is the grouping of several genera (plural of genus) into a family. As with plants within the same genus, plants in the same family have many characteristics in common. Grevillea victoriae is in the family Proteaceae, along with Banksia, Hakea, Macadamia and many other genera. Family names start with a capital letter and generally end in “…ceae”.
There are a number of levels of classification below that of species, with the most commonly used being subspecies and variety, abbreviated to ‘subsp.‘, (or less usefully ‘ssp.‘) and ‘var.‘ respectively. This allows further subdivision of plant groups to reflect the variation in form and distribution we see in nature. These subdivisions, along with species, genera, families and other groupings or ranks within plant classification, are referred to as taxa (plural) or a taxon (singular).
For example, three subspecies are recognised within Grevillea victoriae:
Grevillea victoriae subsp. victoriae – the one closest to the original description of the species.
Grevillea victoriae subsp. nivalis – differing slightly from the original description of the species.
Grevillea victoriae subsp. brindabella – a subspecies described in 2010 from the Southern Tablelands of NSW-ACT.
Whenever a subspecies, variety or other subdivision below the rank of species is published, an additional name, called an autonym, is automatically generated. In the case of Grevillea victoriae above, the publication of Grevillea victoriae subsp. nivalis in 2000 created the autonym Grevillea victoriae subsp. victoriae.
In other words, in 2000 the author chose to recognise a subdivision within the species which differs from what are considered to be “typical” Grevillea victoriae, and named it Grevillea victoriae subsp. nivalis. Plants regarded to represent typical Grevillea victoriae assume the name Grevillea victoriae subsp. victoriae.
When referring to a plant in a genus when we do not know which species it is, we use the generic name followed by ‘sp.‘ ie: Grevillea sp.
When referring collectively to some or all of the species in a genus we use the generic name followed by ‘spp.‘ ie: Grevillea spp.
As noted in the examples above, plant names are usually written in italics within a sentence of plain type, or at least in a different type-face, or underlined, to distinguish them from other words. Family names are not italicised, nor are abbreviations like ‘subsp.’ or ‘sp.’.
The name of a plant is based on an original description, the earliest use of the name generally being the most relevant, dating back as far as 1753 for flowering plants, when Linnaeus published his concept of the binomial naming system.
Each plant name is associated with an original description, including a brief description in Latin (before 2012), which is called a protologue and a nominated ‘type specimen‘ which is an herbarium specimen lodged with a recognised herbarium somewhere in the world.
This original description (the protologue) must be published in a journal or other recognised printed medium. (Since 2012 certain PDF publications on the web, in English, are permitted).
The person/s making this original description in a published journal or book is called the ‘author’ for that plant name, and their name follows the genus and species in a full citation, for example:
Grevillea victoriae F.Muell.
In this case Ferdinand von Mueller (F.Muell. is a standard abbreviation) published the original description for this species in the Transactions of the Philosophical Society of Victoria, Vol. 1, page 107 in 1855. The author name is not written in italics.
Since our knowledge-base and opinions change with time as more becomes known about the plant group in question, the author citation can become quite complicated as it reflects the published opinion of botanists over time. Thus we can have, for example:
Grevillea pyramidalis subsp. leucadendron (A.Cunn. ex R.Br.) Makinson
This name reflects the view of Alan Cunningham in a book published by Robert Brown in 1830, and its status in the opinion of Bob Makinson in 2000 published in the Flora of Australia, Vol. 17A, page 505.
The science of naming plants, or ‘nomenclature’ is governed by a series of internationally accepted rules and regulations, contained in the International Code of Botanical Nomenclature (or ‘Code’ for short). The Code was first formulated 1905, and has since been revised at about six-year intervals, based on a consensus of views of taxonomic botanists from around the world. The current International Code of Botanical Nomenclature is known as the Vienna Code, adopted by the Seventeenth International Botanical Congress in Vienna, Austria, in July 2005. If a plant name is published according to the rules of the Code, we say it is a ‘valid publication’ or it has been ‘validly published‘.
The most recent (18th) International Botanical Congress held in Melbourne in August 2011 will result in a new edition of the International Code of Botanical Nomenclature.
Type specimens (or ‘types’) are an integral part of plant nomenclature. Types are generally preserved plant specimens, lodged in a herbarium, but in certain cases types may also be represented by illustrations. Types serve as the designated ‘standard’ for a particular author’s concept of a published plant name, and they help us determine how names should be applied.
Determining exactly how a particular type specimen affects the application of a particular plant name can be quite complex, and various factors need to be considered. Because of this complexity, the International Code of Botanical Nomenclature recognises many different kinds of types. These are indicated by a prefix before the word ‘-type’, for example: holotype, lectotype, neotype, etc.
Names for cultivars (= cultivated varieties) is more complicated and dictated by another set of rules known as the International Code of Nomenclature for Cultivated Plants, the latest edition published in 2004.
The cultivar name is always added after a valid scientific name at the genus or species level, is not Latinised, is put in single quotes, and is not italicised. ie:
Grevillea ‘Robyn Gordon’ – a cultivar which is a man-made hybrid between two species [photo]
Grevillea rosmarinifolia ‘Rosy Posy’ – a cultivar which is a selected form of a valid species [photo]
Grevillea ‘Rosy Posy’ – is an alternative way of naming this plant, acceptable, but less informative [photo].
For more information on cultivar names, see the web site of the Australian Cultivar Registration Authority.
There is no international convention governing the way common names can be written or used. In fact, in their truest form common names arise from common use by people in contact with the plants – often people who are not aware of the scientific naming of plants.
These true ‘common names’ are therefore in a range of different languages, different scripts and not codified in any way. The same species of plant can have very different common names in different places, and could have different common names in the same place according to different groups of people. Thus Aboriginal and European people living in the same area might each have very different common names for the same plant.
Sometimes names used by one group of people are adopted by another, sometimes the pronunciation gets corrupted in the process. The aquatic fern Marsilea drummondii is now known by the common name ‘Nardoo’, an attempt at converting the spoken Aboriginal name for this plant in one part of Australia into English [another photo].
Using Common (vernacular) Names
There is no universally accepted way of writing common names. However, the following is generally recommended:
Lumley, Peter & Spencer, Roger (1991) ‘Plant Names: A Guide to Botanical Nomenclature’, Royal Botanic Gardens, Melbourne.
1 Red Flowering Gum = Corymbia ficifolia
but there are many different species of red flowering gums, ie eucalypts with red flowers.