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Plant Nomenclature for Beginners

This post looks at plant names and what is important to know

Flowering and non-flowering plants

Only 8% of plants don't reproduce with flowers. Those are:

- Ferns

- Moss

- Conifers

- Horsetail equisetum

- Cycads

- Liverworts

- Clubmoss (there are 4 species of clubmoss in the UK)

- Selaginella (it’s a cone structure which has spores in)
So flowering plants are 92% of the total. Flowering plants evolved 145,000 yrs ago, when the ancestors of algae started to colonise the hearth. Flowering, as a reproductive structure is proven to be very successful.

With the recent climate changes, flowering plants can survive better than non-flowering ones. This is because they produce seeds and seeds are very resistant to changes in temperature.

Grasses are flowering plants, but their flowers don't have petals.

History of plant nomenclature

Throughout the middle age each institution had their own ways to talk about plants and describe them. There was no agreement on names and people referred to plants with a description and the description was the name. It varied from one country to another and from one university to another. In 1753, Carl Linnaeus, a Swedish botanist, publishes a new system to organise plant names. Linnaeus is today known as the father of modern taxonomy. He organised plant nomenclature and it’s now well established and utilised everywhere in the world.

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Current plant nomenclature

Nowadays we have the International Code of Nomenclature for Cultivated Plants (ICNCP) last edition is from 2009. After Carl Linnaeus a lot of names for plants have been made redundant. There are also synonyms names.

Each living creature has 2 names:
1) a genus
2) and a species
Both parts of the name are always written in italics.
If you handwrite the names and you want to indicate they are in italics, you underline them.

Only the Genus has a capital letter, the species is always written in lowercase.

The subdivisions is:
The plant kingdom:
- Clade
- Order
- Family
- Genus
- Specie

- Subspecies (Always abbreviated: subsp. or ssp.)

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(plural Genera)

e.g. Rhododendron it the genus, which has inside thousand of species.


The difference in DNA determines the species. There are about 400,000 different species of plants on the panet. Individuals in the same specie can interbreed. Species names are always in lower case.

Subspecies (always abbreviated in subsp. or ssp.). E.g. Quercus robur subsp. pedunculflora. Subspecies with English names are not italicized. Subspecies are always written in lower case.

Varieties and forms

(Abbreviated to var. Or v.) A variety is a minor genetic difference and may just describe one specific individual.
E.g. Quercus robur f. fastigiata

Fastigiata describes the shape. This shape of oak tree occurred in the wild in Scotland in the 70s and it was then propagated all over the UK.

When describing varieties and forms, Latin names are italicised, but not English words.

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E.g. Quercus robur x Q. petraea

The second time we write the genus, it needs to be abbreviated with the first letter in uppercase. x cross indicated the hybrid.

Sometimes an hybrid can have its own name. Usually we write the whole foruma if the hybrid occurred in nature, but it will have its own name if it was done deliberately, e.g. Erica x watsonii (Obviously designed by someone named Whatson).
Why do we hybridise? To create novelty, because the public loves horticultural novelty. Another reason is to create hybrid vigour. So hybridised plants become more vigorous and we get something new. We are perfectioning the plants.

David C.H. Austin is a 92 y/o famous gardener for creating hybrids of roses. He says his goals are:

- To maintaining the character of the rose

- To create a better scent

- To increase disease tolerance and resistance

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If I can produce a good hybrid, it can become a cultivar. Cultivars usually have catchy names.
E.g. Quercus Robur ‘Atropurpurea’(This is an oak with purple leaves)
Capital letters, non italicized in English or a Latin or a name in single quotation marks

Cultivars are plants that exhibit desirable characteristics, for example: vegetables and fruits for the supermarkets will be bread not to bruise during transportation.
All cultivars are genetically identicals. They are made in a lab for mass production, e.g. the plants that are sold in Ikea.

Group, Grex and Series
(Grex means flock in Latin)
They are all similar, but not identical. If they were identical they would be cultivars. They are genetically different.
E.g. Actaea Simplex (Atropurpurea Group) ‘Brunette’
All the individuals in the atropurpurea group will be similar, but not identicals. ‘Brunette’ is the name of the cultivar. All the ‘Brunette’s will be genetically identical.


After the name of the plant, sometimes there is an initial capital letter. This is the first letter of the surname of the first person who discovered or named the plant. E.g. L. stands for Linnaeus.

Trade designation and trademarks
PBR is the Plant Breeders Rights. A plant with a designation or trademark is the same as a cultivar, but the trade name is not in quotation marks.
E.g. Choisya ternata Sundance

Plant breeders can apply for the PBR certification and will have it for 2 years. After 2 years the PBR elapse and anyone can reproduce or sell the plant