PLANT DIVERSITY
Lecture 1
Plant Systematics and
Linnean taxonomy
Lecturer: Asst. Prof. Dr. İsmail EKER
Common misconception
Taxonomy is very difficult and specialized
FACT: Taxonomy is part of the cognitive
process.
Everyone is a taxonomist!
What is Classification?
• Classification is the
arrangement of organisms into
orderly groups based on their
similarities
• Classification is also known as
taxonomy
• Taxonomists are scientists that
identify & name organisms
Why we need Latin names?
Common names ??
NOT UNIVERSAL!!
Problems:
1. They are too many!!!
Nymphaea alba L. has:
15 in English
44 in French
105 in German
81 in Dutch
221 in Russian
…over 5000 common names
worldwide!
Latin Names are Understood
by all Taxonomists
2. Many plant species do
not have a common
name
e.g. ~2000 spp. of Carex L.
are called “sedge”
3. Different plants may have the
same common name
Often, two or more unrelated species are known by the same
common name.
e.g. Bachelor‘s button, may thus be Tanacetum vulgare L.,
Knautia arvensis Coult. or Centaurea cyanus L.
Tanacetum vulgare L.
Knautia arvensis Coult.
Centaurea cyanus L.
4. many common names may
exist for the same species in
the same language in the same
or different localities.
e.g. Cornflower, bluebottle,
bachelor‘s button and ragged
robin all refer to the same
species Centaurea cyanus L.
Centaurea cyanus L.
Why Latin?
The selection has several advantages over modern
languages:
i) Latin is a dead language and as such meanings and
interpretation are not subject to changes unlike,
English and other languages
ii) Latin is specific and exact in meaning
iii) grammatical sense of the word is commonly
obvious
iv) Latin language employs the Roman alphabet,
which fits well in the text of most languages.
Early Taxonomists
•2350 years ago, Aristotle
(384-322 BC) was the
“first taxonomist”
•Aristotle divided
organisms into plants &
animals
•Aristotle was the first to
attempt to classify all the
kinds of animals in his
“Historia Animalium” in
Latin.
Early Taxonomists
• Aristotle’s student
Theophrastus (372-287 BC)
known as the "father of
botany“
•His “De Historia Plantarum”
is the first written
literature about plants.
•He first described the
anatomy of plants and
classified them into trees,
shrubs, herbaceous
perennials, and herbs.
Early Taxonomists
• John Ray (16271705), a botanist,
was the first to
use “Polynomial
system” naming of
plant in Latin
• His names were
very long
descriptions
telling everything
about the plant
Polynomial system [before 1800]
Polynomial Nomenclature
• Ranunculus calycibus,
retroflexus, pedulculis
falcatis, caule erecto, folis
comopositis
• “The buttercup with bentback sepals, curved flower
stalks, erect stems and
compound leaves”
Carolus Linnaeus
1707 – 1778
• Swedish scientist – Carl von Linne
(doctor and botanist)
• Called the “Father of Systematic
Botany”
• Established modern system of
nomenclature
• His binomial system of
nomenclature, in which the genus
and species names are used.
Binomial system
Linnaeus, Species Plantarum (1753)
Dianthus caryophyllus L.
• Genus (pl. genera)
• Always capitalized
• Abbreviated on 2nd
use
Abbreviation of
• Specific epithet
author who
• Not capitalized
discovered and
• Often a
described the species
descriptive
neither italicized nor underlined
adjective
italicized or underlined
Binomial = 2 names
The genus comes first and is always capitalized and italicized
The specific epithet comes after the genus and is always lower case and italicized
Photographed by Eker
Allium arsuzense Eker & Koyuncu
genus specific epithet
Author(s)
species (taxon) name
Photographed by Eker
Allium roseum L. subsp. gulekense Koyuncu & Eker
subspecies
At a meeting in Paris in 1867, European &
American botanists agreed to use Linnaeus’
binomial classification as the starting point for all
scientific names of plants. The rules were drawn
up at that meeting and these rules today have
been revised at International Botanical Cogress
by
ICBN
commitee,
lastly
held
at
Melbourn/Australia in 2011.
International Code of Botanical
Nomenclature (ICBN)
Guidelines set by the ICBN
1. Botanical nomenclature is independent of
zoological nomenclature.
International Code of Botanical
Nomenclature (ICBN)
2. Each taxon can have only one correct name.
International Code of Botanical
Nomenclature (ICBN)
3. Each name must be linked
to a type specimen.
International Code of Botanical
Nomenclature (ICBN)
4. Nomenclature of taxonomic groups is based on
priority of publication
Polygonum aviculare L. , Species Plantarum 2: 362. 1753
journal name
vol. page date
Polygonum heterophyllum Lindman, Svensk Bot. Tidskr. 6: 690, 1912.
Taxonomic ranks (taxa)
(e.g. house, street, city, county, state, country, continent, planet)
Taxonomic ranks (taxa)
The dendrogram view of Taxonomic hierarchy
What is a species?
Species: a set of individuals that are closely
related by descent from a common ancestor
and ordinarily can reproduce with each other,
but not with members of any other species.
Biological species: a group of interbreeding
populations. Offspring are fertile.
“sp.” or “spp.” stands for species and never underlined or italicized
singular plural
e.g. Allium L. sp. has a meaning of 1 Allium species
Allium L. spp. have a meaning of more than 1 Allium species
Species
Some members of same species look very
different…
All these are same species!
Same species, are capable of interbreeding, but Morphologically may
look very different.
Broccoli, kale, cabbage, cauliflower: members same species!
Brassica oleracea L.
Broccoli: brokoli: Brassica oleracea ‘Italica Group’
Brussels sprouts: Brüksel lahanası: Brassica oleracea ‘Gemmifera Group’
Cabbage: lahana: Brassica oleracea ‘Capitata Group’
Cauliflower: karnıbahar: Brassica oleracea ‘Botrytis Group’
Kale: kara lahana: Brassica oleracea ‘Acephala Group’
Plant species can be divided more
specifically into:
• subspecies
• variety
• hybrid
• cultivar
SUBSPECIFIC CATEGORIES
Subspecies
A subspecies describes a group of related organisms that can interbreed
and are geographically distinct from others in their species.
subspecies (abbreviated "subsp." or "ssp."; plural: "subspecies")
Photographed by Eker
Allium roseum L. subsp. roseum
Allium roseum L. subsp. gulekense Koyuncu & Eker
The Variety
• A group of plants subordinate to the species; differing
from the species in one or more inheritable
characteristics.
• Written in lower case and italicized or underlined.
•“var.” from Latin varietas, “variety”
Cercis canadensis L.
Cercis canadensis L. var. alba (Rehder) Bean
Hybrids
• two closely related but distinct species will be interbreed to
form a hybrid
• are often sterile and produce no seed or fruit
• written in lowercase and italicized or underlined
• an “x” is placed between the genus and hybrid epithet. the
“x” means the plant is a hybrid.
Platanus occidentalis L. crossed with Platanus orientalis L.
Platanus x acerifolia (Aiton) Willd.
The Cultivar (“Cultivated variety” or horticultural variety)
•
•
•
•
In ornamental horticulture cultivar characteristics are not inheritable
Cultivar names are always capitalized and never underlined/italicized
Written in single quotations or with abbreviation of cultivar (cv.)
Example: Cercis canadensis ‘Forest Pansy’
OR
Cercis canadensis cv. Forest Pansy
• A single species may have many cultivars
Juniperus horizontalis ‘Blue Chip’
Juniperus horizontalis ‘Plumosa’
Juniperus horizontalis ‘Hughes’ etc.
• Plants within a species that have been selected especially for a
particular characteristic and are propagated, usually asexually to
continue this trait(growth habit, flower, fruitless).
Viburnum opulus L.
Viburnum opulus ‘Roseum’
Viburnum opulus cv. Roseum
It is possible to have a cultivar of a variety
Gleditsia triacanthos inermis ‘Skyline’
Cornus florida rubra ‘Cherokee Chief’
Gleditsia triacanthos L. var. inermis ( L. ) Castigl.
Gleditsia triacanthos var. inermis ‘Skyline’