LO 1.1 - Binomial system of nomenclature

Question 1

Describe the Binomial Classification System.

Answer 1

The Binomial Classification System.

• Arrangement of organisms based on their similarities - For plants it is botanical similarities.
• Grouped into families according to the structure of their flowers, fruits and other organs.
• Taxonomy - Latin or sometimes Greek.
• Common names - are confusing.

Answer 2

18th Century Swedish Taxonomist - CARL LINNAEUS (1707 – 1778).

• He worked on classifying organisms (animals, plants and minerals).
• Plants were classified by their botanical structure.
• Two names for each species, Generic specific. e.g. Homo sapiens.

Question 3

The Binominal System is controlled by two international codes:

Name them.

Answer 3

1. International Code of Botanical Nomenclature (ICBN) - control the botanical naming of plants (both wild and cultivated).
2. International Code of Nomenclature for Cultivated Plants (ICNCP) - control the naming of cultivars and group species.

Question 4

Plant names are made up of Generic Specific (in italics) and ‘Cultivar’ (single quotes) names.

Review it.

Answer 4

Question 5

Family names in the Binomial system always end in…

Answer 5

ACEAE

Families - structure of flowers, fruits and other organs

They always ends in ‘ACEAE’ – translates as ‘resemblance’

Answer 6

SURNAME

Genus (generic) __surname __similar features

E.g. Oaks are characterised as having a singular seed.

genus Quercus has over 600 species.

Answer 7

FIRST NAME

Specific (Specific Epithet) like a first name

Often describes some aspect of the plant – colour of flower, size/shape of leaves, place of origin

Answer 8

Very Important rules for writing Botanical names.

• Genus and specific names are always written in italics.
• Genus or generic will always start with a CAPITAL LETTER.
• Specific will always be in lower case.
• If a species is unknown it will be abbreviated to Generic followed by sp.

Below is Betula pendula ‘Youngii

Question 9

SPECIES SUBDIVISION.

Commonly plants of the same species in the wild can exhibit slight differences in their botanical make-up.

Three botanically recognised subdivisions were created to individually allow identification and naming of these subdivisions.

Species can therefore be further subdivided into:

Answer 9

1. Subspecies
2. Varieties
3. Forms

Question 10

SUBSPECIES

Describe when SUBSPECIES is used and how it’s written.

Answer 10

SUBSPECIES

• Used as recognition of naturally occurring geographical variations within a species where there is a DISTINCT variation.
• Subspecies is written as subsp. always in lower case Roman and full stop.

DISTINCT GEOGRAPHICAL VARIATION

Question 11

VARIETY

Describe when VARIETY is used and how it’s written.

Answer 11

VARIETY

• Used as recognition of variations differing slightly in botanical structure such as shape, growth habit, leaf shape.
• Variations not as insignificant as in a form and never attributed to geographical or regional differences.
• Written as var. always in lower case Roman and full stop.

SLIGHT VARIATION IN BOTANICAL STRUCTURE

Question 12

FORM

Describe when FORM is used and how it’s written.

Answer 12

FORM

• Used as recognition of only MINOR variations such as colour of leaf, flower, habit etc.
• Examples include f. alba – white form of a species .
• Written as f. always in lower case Roman and full stop.

MINOR VARIATION

Question 13

CULTIVAR

Describe what CULTIVAR is in plants.

Answer 13

CULTIVAR.

A plant differing in cultivation from the wild form of the species is described as a cultivar.

OR

A plant variety that has been produced in cultivation by selective breeding.

Question 14

CULTIVARS

REVIEW IN DETAIL

Answer 14

CULTIVARS

• These forms are of interest for their horticultural importance, variegated leaves, larger petals, habit and etc.
• They are introduced to cultivation, with many propagated vegetatively or, grown annually from selected seed.
• They reproduce reliably and can easily be maintained in cultivation.
• New cultivars named since 1959 must be given vernacular names.
• They are always written in Roman type within quotes.

Question 15

HYBRID

Describe what a HYBRID is in plants.

Answer 15

HYBRID

Some plants species when grown together – either in the wild or in cultivation - are found to be interbred

Question 16

HYBRID

How does hybridation occur in plants?

Answer 16

HYBRID

When sexual crosses between botanically distinct species or genera occurs.

The resulting offspring are known as Hybrids and the majority occur between species within a single genus.

A ‘formed Hybrid’ is a unique plant with its own characteristics.

Written as a multiplication sign X.

Question 17

In a hand written document, how should names be written?

Answer 17

Italics should be replaced with an UNDERLINE.

Question 18

REVIEW

Binomial Family Tree.

Answer 18