The naming of cultivated plants
The binomial system
The name given to a plant species is very important. It is the key to
identification in the field or garden, and also an international form
of identity, which can lead to much information from books and the
Internet. The common names which we use for plants, such as potato
and lettuce, are, of course, acceptable in English, but are not universally
used. A scientific method of naming can also provide more information
about a species, such as its relationship with other species.
Linnaeus, working on classification and with the more detailed question
of naming, formulated a system that he claimed should identify an
individual plant type uniquely, by means of the composed genus name
followed by the species name. For example, the chrysanthemum used
for cut flowers is Chrysanthemum genus and morifolium species; note
that the genus name begins with a capital letter, while the species has
a small letter. Other examples are Ilex aquifolium (holly), Magnolia
stellata (star-magnolia), Ribes sangui-neum (redcurrant).
Subspecies can evolve and display more distinct characteristics than
the varieties detailed below, e.g. Rhododendron arboreum subsp. cinnamomeum. The genus and species names must be written in
italics, or underlined where this is not possible, to indicate that they
are internationally accepted terms. However, these two words may not
encompass all possible variations, since a species can give rise to a
number of naturally occurring varieties with distinctive characteristics.
In addition, cultivation, selection and breeding have produced variation
in species referred to as cultivated varieties or cultivars.
The two terms, variety and cultivar are exactly equivalent, but the
botanical variety name is referred to in Latin, beginning with a small
letter, e.g. Rhododendron arboreum var roseum, while the cultivar is
given a name often relating to the plant breeder who produced it, e.g. Rhododendron arboreum 'Tony Schilling'. There is no other significant
difference in the use of the two terms, and therefore either is acceptable.
However, the term cultivar will be used throughout this text. A cultivar
name should be written in inverted commas and begin with a capital
letter, after the binomial name or, when applicable, the common name.
Examples include: Prunus padus 'Grandiflora', tomato 'Ailsa Craig',
apple 'Bramley’s seedling'.
If a cultivar name has more than one acceptable alternative, they are said
to be synonyms (sometimes written syn.) e.g. Phlox paniculata ‘Frau
Alfred von Mauthner' syn. P. paniculata 'Spitfire'.
When cross-pollination occurs between two plants, hybridization
results, and the offspring usually bear characteristics distinct from
either parent. Hybridization can occur between different cultivars
within a species, sometimes resulting in a new and distinctive cultivar, or between two species, resulting in an interspecific
hybrid, e.g. Prunus × yedoensis and Erica × darleyensis. A much rarer
hybridization between two different genera results in an intergeneric hybrid, e.g. × Cupressocyparis leylandii and × Fatshedera lizei. The
names of the resulting hybrid types include elements from the names
of the parents, connected or preceded by a multiplication sign (×).
A chimaera, consisting of tissue from two distinct parents, is indicated
by a 'plus' sign, e.g. + Laburnocystisus adamii, the result of a graft.