Botanical name
Every plant has a formal name which is recorded in the ‘International Code of Botanical Nomenclature’ and becomes the single accepted name for that particular plant. In some cases synonyms are also accepted, for example Tulipa ‘Madame Lefeber’ is also known as Tulipa ‘Red Emperor’.
The botanical name can be broken down into several parts:
Genus
This is a Latin or Latinised word for the wider group of plants which this particular species belongs to. Examples of plant genera would be Anemone or Camellia. Genera are always written in italics and start with a capital letter.
Species
A subset of genus, the plant’s species name is again written in Latin or Latinised language, is in italics, but does not have a capital letter. Every plant will have a species, although it may not have any of the lower sub sets listed below. The species name often describes something about the plant, for example with Camellia japonica the species name of ‘japonica’ describes the geographical origins of the plant. With Anemone sylvestris, the species name ‘sylvestris’ relates to the fact that this is a woodland growing plant.
Variety
A variety occurs when something slightly different happens to a group of plants from a particular species, for example if some plants start to have different coloured flowers. While this is a similar situation to the ‘Form’ and ‘Cultivar’ names below, the difference with a variety is that it has to be a self-sustaining population. A variety name is written in lower case and italics and is either in Latin or Latinised. It is often proceeded by ‘var.’.
Form
A form is similar to a variety in that it is a variation on the species (or on a variety), but the variation does not occur in a population of plants which is self-sustaining. Forms can become varieties if the population stabilises. Forms are written in non-italics and are often proceeded by ‘f.’.
Cultivar
A cultivar is usually a hybridised form of a plant which cannot sustain itself (ie if you sow the seeds from it they will not come true to form). Usually, but not always, cultivars are man-made crosses. Cultivar names are the only ones which don’t have to be written in Latin or Latinised, they can be in the language of the creator of that cultivar.
While having a botanical name in Latin does give quite an ‘elitist’ feel to horticulture, it’s actually a very practical solution to the international problem of being able to communicate accurately about plants. Using common names has disadvantages both in terms of communication between people of different languages and because it’s a pretty inaccurate way of identifying individual plants.
Oddities!
X marks the spot
Sometimes you’ll see a ‘x’ in the plant name. This indicates that the plant is a result of two other plants being crossed (hybridised). Where the cross is between two plants of the same genera but different species (such as Magnolia denudata and Magnolia liliiflora) the ‘x’ goes between the two names chosen for the new plant (ie Magnolia x soulangeana). Other examples of these ‘interspecific hybrids’ include Prunus x yeodensis and Erica x darleyensis.
Where the cross is, more rarely, between plants from two different genera (such as Heuchera sanguinea and Tiarella cordifolia the ‘x’ goes before the plant name (ie x Heucherella tiarelloides). These are known as ‘intergeneric hybrids’. Further examples include x Cupressocyparis leylandii and x Fatshedera lizei.
+ more
On rare occasions a ‘chimera’ occurs between two plants of different genera. This happens when two plants of different genera are grafted together and the genetic tissues of the two plants exist together as a new plant (unlike a normal graft where the rootstock and scion continue to grow as two separate entities, simply sharing food and water). When this occurs a ‘+’ is used at the start of the name of the new plant. An example of a chimera is + Crataegomespilus which was created from the genera Crataegus and Mespilus.
No species name
Some plants, such as many roses, only have a Genus name followed by their cultivar name. For example, Rosa ‘Elizabeth Harkness’ or Tulipa ‘Olympic Flame’. This is usually because the origin of the plant has been lost in the numerous hybridisations used to create the particular cultivar.
