© Garden Cottage Nursery, 2021
How Plants Are Named And
Grouped
Taxonomy
Along with an accepted form of making a botanical name there
is also an accepted way of writing them in print:
The whole should be in italics so you can see straight away that
it is a botanical name and the first letter of the Generic name
should be capitalised and the specific name all lower case, even
if it is derived from a proper noun.
Garden forms or ‘Cultivars’ should be named after the binomial,
they should not be in italics, appear inside single quotes and be
capitalised. For the last 25 years or so all new cultivar names
should also not be in Latin to avoid them being confused with
species, e.g. if you found a new oak tree with blue acorns you
couldn’t name it Quercus robur ‘Glans Caerulea’ but you could
call it Quercus robur ‘Blue Acorn’. Old cultivar names haven’t
been changed, so Quercus cerris ‘Argenteovariegata’ retains it’s
name as it has been around for decades. If you are not
multilingual vernacular cultivar names can lead to some
consternation when you buy a “Sedum Autumn Joy” not
realising that a helpful anglophone nurseryman had translated
the cultivar name from German for you and it is infact the
Sedum 'Herbstfreude' you already had in your garden. Also
getting our Scottish tounges around Dutch vowels can be a bit
of a challenge!
Supra Generic, Higher Levels
To help sort out the relationships between different organisms
names are given to different ranks to flesh-out the branches of
the family tree so, for the sessile oak:
Kingdom: Plantae - All plants
Phylum: Magnoliophyta - Flowering plants (Angiosperms)
Clade: Eudicots - ‘True’ dicotyledons
Clade: Rosids - Large group containing over ¼ of angiosperms
Order: Fagales - Contains 7 families of forest trees
Family: Fagaceae - Mostly deciduous trees of temperate and
sub-tropical forests including, oak, beech and sweet cheasnut
Genus: Quercus - Oak trees of which there are around 600
species around the Northern Hemisphere.
Species: patraea - the sessile or durmast oak native the forests
Europe including Scotland.
Gardeners don’t really need to know about these ranks above
the genus names, but the family name can be quite useful to
know as similar characters are often shared across a family’s
different genera, e.g. oaks, beeches and chestnuts are all in the
Fagaceae and all plants with daisy flowers are in the
Asteraceae.
Infra Specific, Lower Levels
There are three more ranks below species level that gardeners
will regularly encounter, these are always preceded by an
abbreviation of what rank is being referred to.
In descending order of rank they are:
The subspecies, which is written in lower case and not in italics
as either “subsp.” or “ssp.” the second is the way we use, e.g.
Primula capitata ssp. mooreana
The variatas, which is written in lower case and not in italics as
“var.”, e.g. Geranium sanguineum var. striatum
The forma, which is written in lower case and not in italics as “f.”,
e.g. Geranium maculatum f. albiflorum
So these can be combined to form truly marathon length names
like Narcissus bulbocodium ssp. bulbocodium var. conspicuus
Where a plant is a hybrid of two different know species it is
sometimes given a new named with a lower case “x”, not
italicised before the italicised new name, e.g. Quercus x
hispanica is Quercus cerris, the Turkey oak crossed with
Quercus suber, the cork oak.
Rarely plants from to related genera can cross to create a
bigeneric hybrid. Their generic name becomes a compound of
the parent genera preceded by an “x”, e.g. × Cuprocyparis
leylandii which is Cupressus macrocarpa crossed with
Xanthocyparis nootkatensis.
The naming of naturally occurring taxa is governed by
International Code of Nomenclature for algae, fungi, and plants.
Cultivated plants often have certain seed strains and
horticulturally related groups within a species or as a complex
series of hybrids within a single genus, for such aggregations
the phrase “Group” is used, e.g. Phormium tenax Purpureum
Group for purple leaved seed raised New Zealand flax.
Cultivars should be clones or show little perceptible variation
and the vast majority cannot be raised from seed and remain
true to type and therefore have the right to that capitalised name
enclosed in single quote marks, e.g. Fuchia magellanica ‘Lady
Bacon’.
“Group” plants however cover a range or more aptly, a theme,
so can often have been seed raised, as long as the offspring still
fit within the theme.
The naming of taxa raised by man is governed by International
Code of Nomenclature for Cultivated Plants.
For some large genera (i.e. a genus with lots of different
species) the relationships between the species within the genus
has been mapped and ranked by botanists.
For some of these large genera it is of interest to the more
serious gardener as they can give an idea of likely
characteristics and cultural requirements.
The most commonly encountered are those for ‘species’
Rhododendrons. For Rhododendron there is a full range of sub-
generic, supra-specific ranks (after Chamberlain and Cullen
system):
Genus: Rhododendron
Subgenus: Hymenanthes - includes many of the most familiar
larger leaved species, characterised by their lack of lepidote
scales on the back of their leaves
Section: Pontica - includes all species within the Subgenus
Subsection: Arborea - includes 3 different species from W
China, Himalayas and Sri Lanka
Species: niveum - a tree sized purple flowered species
found in E Himalayas
With Rhododendron the Subsection is the most often used by
gardeners and nurserymen to give an indication of the sort of
Rhodo that is being discussed, however Rhododenrons are
amazingly profligate so most garden cultivars are complex
hybrids with ancestors from multiple subsections.
With Primula it is Section, e.g Prolifera for candelabra types,
that is commonly used.
All living things are “Properly” named in the same way, e.g. we
are Homo sapiens.
Continue to page 2 for an attempt to explain why plant names
sometimes get changed.
People have tried to give names to living things as long as there
have been people, the problem that there is an awful lot of
different things to name and people like to make up new names
or people will give a new name to something that unbeknownst
to them someone else has already given another name.
Many plants and animals cover extensive natural ranges and as
such over the centuries they have acquired several common
names, e.g. oak in English, is called darach in Gaelic, eiche in
German, chêne in French and roble in Spanish.
In the 18th century the Lingua Franca of the Europe was Latin,
so when botanists wanted to refer to a plant to someone not
from their country they would name it by giving it a great big
long description in Latin. Of course this descriptive name could
be a little bit different every time it was used, it was not a good
system. To make things simpler a single universally agreed
system would be good and in 1753 a Swedish botanist called
Carl Linnaeus published a new, simple and sensible system for
naming plants and animals properly. He suggested giving
everything a name in two parts (a binomial), which together
would be unique so avoiding duplication and confusion.
The idea was that the first name would be of the group to which
the plant belonged; often this was the Roman common name,
e.g. quercus for oak became Quercus to refer to all oak trees
wherever they come from and of whatever sort they are. This
part is called the Genus. The second part of the name, the
species, tells you exactly what type of plant it is. Sometimes this
name is descriptive, e.g. Quercus rubra, the red oak, noted for
its red autumn colour. Sometimes the species name
commemorative of a person, e.g. Quercus douglasii, named for
Scottish plant hunter David Douglas. Other times the specific
epithet may give a clue as to where the plant originates or the
sort of place it grows, e.g. Quercus mexicana from Mexico or
Quercus palustris meaning ‘of the marsh’.
What the species name is isn’t really important, as long as there
isn’t another species within that genus with the same name.
Plant and animal names are not actually named in ‘Classical
Latin’ but rather a sort of mixture with Ancient Greek and Latin
referred to as ‘Botanical Latin’.
Since the 1990s in Europe systems for patenting plant varieties
have existed. Generally what happens is a large grower or
corporation will run an extensive breeding programme to raise
new variety or series of varieties with various desirable
characters, they will then register the variety/s with Plant
Breeders Rights giving it both a valid cultivar name and a more
marketable trade designation, e.g. the black cut-leaf elder
Sambucus nigra f. porphyrophylla 'Eva' is sold as Sambucus
nigra Black Lace, note the lack of single quotes around Black
Lace as it isn’t a cultivar name.
Anybody in the EU who propagates a plant with Plant Breeders
Rights for commercial sale must pay the rights holder a royalty.