DRAFT · not live yet · buttons are placeholders
Free lessonUnit 1 exam · Topic 1 · Learning outcome 1 (1.1, 1.2)

How plants are named

Taxonomy from family to cultivar, how to write each part of a plant name for full credit, and how Plant Breeders' Rights protect new cultivars.

Key points

TaxonomyFamily (-aceae) → genus → species (genus + epithet) → cultivar.
FormattingGenus capital, species lower case, both italic (underlined by hand); cultivar in single quotes, not italic.
Variety, cultivar, hybridvar. occurs naturally; a cultivar is selected by people; a hybrid (×) crosses two species, or occasionally two genera.
PBRIntellectual property for a new cultivar: royalties for the breeder; no propagating for sale without a licence.

Summary

TermMeaningWritten asExample
TaxonomyThe science of classifying and naming plantsn/an/a
FamilyA group of related generaCapital; usually ends -aceaeRosaceae
GenusA group of closely related speciesCapital, italicMalus
SpeciesGenus + specific epithetGenus capital, epithet lower case, both italicMalus domestica
CultivarSelected and maintained in cultivation by peopleCapitals, single quotes, not italicMalus domestica 'Bramley's Seedling'
VarietyNaturally occurring variation within a speciesvar. (not italic)Salix alba var. vitellina
HybridCross between two species (interspecific) or two genera (intergeneric)× between genus and epithetMagnolia × soulangeana; ×Heucherella
Plant Breeders' RightsIntellectual property protection for a new cultivarPBRRoyalties; licence to propagate for sale

When handwriting, underline the genus and species instead of using italics.

Test yourself

Which part of a plant name is written in single quotation marks?
  1. Genus
  2. Species
  3. Cultivar
  4. Family
Answer: C. Cultivar names start with capitals, are not italic, and sit in single quotes: Malus domestica 'Bramley's Seedling'.
What does the × in Magnolia × soulangeana show?
  1. It is a hybrid between two species
  2. It is a naturally occurring variety
  3. It is protected by Plant Breeders' Rights
  4. It is a sterile cultivar
Answer: A. The multiplication sign shows a hybrid. Here the parents are two Magnolia species.
Which is a benefit of Plant Breeders' Rights to the breeder?
  1. The plant becomes resistant to pests
  2. They earn royalties when the cultivar is propagated
  3. The cultivar can be sold without labels
  4. The species name can never change
Answer: B. PBR are intellectual property rights. Royalties let breeders recover the cost of developing the cultivar.

Video transcript

Every plant has one accepted scientific name, recognised worldwide. In this lesson: how plants are classified, how to write each part of a name correctly, and how Plant Breeders' Rights protect new cultivars.

Taxonomy is the science of classifying and naming plants. A family groups related genera, and family names usually end in aceae, as in Rosaceae, the rose family. A genus is a group of closely related species, such as Malus, the apples. The species name pairs the genus with a specific epithet: Malus domestica. And a cultivar is a cultivated variety, selected by people, such as Malus domestica 'Bramley's Seedling'.

Writing names correctly earns marks. The genus starts with a capital letter, and the species is all lower case. Both are written in italics, or underlined when handwritten. The cultivar name is not italic. It starts with capitals, and sits in single quotation marks.

Three terms are often confused. A variety, written var., is a naturally occurring variation within a species. A cultivar is selected, and maintained in cultivation, by people. And a hybrid is a cross between two different species, shown in the name with a multiplication sign.

Plant Breeders' Rights give legal protection to a new cultivar. They are a form of intellectual property, like a patent. The breeder earns royalties when the cultivar is propagated and sold. So propagating a protected cultivar for sale, without a licence, is not allowed. Breaking the rules can lead to fines and legal action.

One exam tip. A definition question wants a precise meaning, not everything you know. For example: a cultivar is a plant selected by people for desirable characteristics. That's the key idea. And maintained in cultivation, usually by vegetative propagation. That makes it precise, and earns the second mark.

This is one of 33 lessons in Unit 1

The full course adds sorting drills, flashcards, a written question with a model answer, and a printable sheet for every lesson.

See the Unit 1 course