Taxonomy And International Code of Botanical Nomenclature - PowerPoint Presentation

Slide1

Taxonomy And International Code of Botanical Nomenclature

Dr. Harsh

Manchanda

Assistant Professor

P. G. Govt. College for Girls

Sector -11

ChandigarhSlide2

TAXONOMY

Plant Taxonomy is a science that includes Identification, Nomenclature &Classification of plants.

Taxonomy= ‘

Taxis’+’Nomous

’

Taxis means Arrangement &

Nomous

means Law or Rule.

Thus , it means classification following certain rules or principles.

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AIMS AND OBJECTIVES OF PLANT TAXONOMY

To identify and give scientific names to all the plants both existent or fossils.

To find out the similarities and differences between the plants identified and named.

To arrange the plants in a regular sequence.

To provide an inventory of plant

taxa

by means of flora.Slide4

5.To devise a natural system of classification and to assign proper status to group of plants

6. To find out the evolutionary history of a species and to find its relation with others.

7. To construct rules and regulations governing the method to name a species ,genus or family.Slide5

NOMENCLATURE

A System of naming plants and animals.

The system of naming Plants on scientific basis is known as Plant Nomenclature

. Slide6

COMMON NAMES

The names given to plants on the basis of language of that locality

in which the plants are growing are known as Common Names or Vernacular Names.

Slide7

Why the common names are disadvantageous?

Only scientific names are universal, used the same world-wide; e.g.,

Hibiscus

- for China rose in English,

Gurhal

in Hindi &

Jaba

in Bengali.

2. Common names are not consistent.

a) A

taxon

may have more than one common name

b)

One common name may refer to more than one

taxon

(e.g.,

”hemlock” for both

Tsuga

and for

Conium

maculatum

).

3. Many of the organisms have no common name in any language.

4. Common names tell nothing about rank.

5. Common names are misleading.Slide8

SCIENTIFIC NAMES

To overcome the problem raised by common names , botanists have given scientific names to all the known plants, for International communication. The language selected for this

Naming was LATIN. Because:

This language is not being used by any country or nation at present.

Most of the European language

s are derived from Latin.

It is considered to be a dead language.Slide9

BOTANICAL NOMENCLATURE

Botanical nomenclature is the formal scientific naming of plants. In early attempts plants names were usually polynomials e.g.,

Caryophyllum

saxalitis

,

folis

gramineus

, umbellate

corymbis

. This cumbersome system was replaced by Binomial Nomenclature devised by Linnaeus in 1753 in

Species

Plantarum

.Slide10

Carolus

Linnaeus

1707-1778Slide11

BINOMIAL NOMENCLATURE

In this system ,a botanical name consisted of two

latinized

words, a generic name followed by a specific epithet e.g., the botanical name of Sunflower is

Helianthus

annuus

. Here,

Helianthus

designates genus and

annuus

designates species of this genus.Slide12

GENERIC NAME

Generic name is usually a noun and singular & may have different types of origin:

(a) A genera may be named in

honour

of a botanist or horticulturist or may be a patron of botany e.g.,

Linnaea

in

honour

of Linnaeus

(b)Some generic names are of poetic or mythological origin e.g.,

Nymphaea

denotes lovely water nymphsSlide13

SPECIFIC EPITHET

The specific epithet is an adjective & may have several origins:

It may be in

honour

of a person e.g.,

hookeri

for Hooker

It may be derived from special characteristics of the plant e.g., alba for white flowered plantSlide14

(c) It may be derived from a geographical location where the plant grows.

(d) It may originate from an old common name.

(e)It may be named arbitrarily.

Generally, the specific epithet is of one word but if it has two words then a

hyphon

should be placed between them.Slide15

Sometimes nomenclature may be of

TRINOMIAL or

QUADRINOMIAL

type.

In trinomial the third epithet is of SUBSPECIES & in

quadrinomial

fourth epithet is of VARIETY.Slide16

INTERNATIONAL CODE OF BOTANICAL NOMENCLATURE [ICBN]

In the nineteenth century it became increasingly clear that there was a need for rules to govern scientific nomenclature, and initiatives were taken to produce a body of laws. These were published in successively more sophisticated editions. For plants the key dates are 1867 (

lois

de la nomenclature

botanique

, ’Paris Code’), 1906 (

International Rules of Botanical Nomenclature

, 'Vienna Rules') ,1952 (

International Code of Botanical Nomenclature

, 'Stockholm Code) and 1994 (Tokyo Code)Slide17

ICBN

The

International Code of Botanical Nomenclature

(ICBN) is the set of rules and recommendations dealing with the formal botanical names that are given to plants. Its intent is that each taxonomic group (“

taxon

", plural "

taxa

") of plants has only one correct name that is accepted worldwide

. Slide18

Principles of ICBN

Botanical nomenclature is independent of zoological nomenclature.

The application of names of taxonomic groups is determined by means of nomenclatural types.

The nomenclature of a taxonomic group is based upon

priority of publication.Slide19

Principles of ICBN

Each taxonomic group (e.g., family or genus or

species) can bear only one correct name: the

earliest

that is in accordance with the Rules, except in specified cases.

Scientific names of taxonomic groups are treated as

Latin

regardless of their derivation.

VI. The Rules of nomenclature are retroactive unless expressly limited.Slide20

RULES OF ICBN

Basic Rules

The complete scientific name includes genus and species, the name of the scientist who first described the species and the year. By convention that the genus and species are written in italics (or, where that is not possible, underlined).   The generic name is always capitalized & the species name is not.Slide21

The first letter of the genus is capitalized; the first letter of specific epithet usually is not.

EXAMPLES:Dianthus

caryophyllus

L.

Rosa

cinnamomea

Dianthus

caryophyllus

or

Dianthus

caryophyllus

“L.” stands for Linnaeus, who is the authority who first named this plant.

When related species in a genus are in a list, it is acceptable after the first species to list them by the first letter of the genus.

EXAMPLE:

Dianthus

caryophyllus

, D.

chinensis

, D.

giganteusSlide22

If we know the genus (eg

. Dianthus) but do not know or do not want to specify the species we can indicate the plant name as follows:

EXAMPLE:

Dianthus

sp.

Or if plural ---

Dianthus

spp.

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TAXONOMIC RANKS

Taxon

is a taxonomic group of plants of any rank e.g.,

Hibiscus

(genus) is a

taxon

,

Malvaceae

(family) is a

taxon

. The rules of nomenclature prescribe the categories for plant classification. These categories or

taxa

constitute the unit s of classification. The basic unit of classification is species.Slide24

A typical Linnaean hierarchy has seven

taxa

represented as follows:Slide25

The extended Linnaean hierarchy may consist of the following taxonomic ranks:Slide26

Categories below the rank of species are:

Subspecies .

Varieties

Sub-varieties

Forma

Clone

Slide27

Phylum [Division

]

-

phyta

Subphylum [Subdivision] -

phytina

Class -

opsida

Subclass -

idae

Super-order -

anae

, [-

iflorae

]

Order -ales

Suborder -

ineae

Family -

aceae

Subfamily -

oideae

Tribe -

eae

Subtribe

-

inae

Major Rank EndingsSlide28

In accordance to ICBN, some traditional names of the families are changed to their alternate names as

(New) (Traditional)

Apiaceae

=

Umbelliferae

Asteraceae

=

Compositae

Poaceae

=

Graminae

Lamiaceae

=

Labiatae

Arecaceae

=

Palmae

Cruciferae

=

Brassicaceae

Slide29

TYPE CONCEPT

The naming of taxonomic group is determined by means of nomenclatural types, where a nomenclatural type is

thatelement

, to which the name of a

taxon

is permanently attached, either as a correct name or as a synonym.

Slide30

Some of the imp. Nomenclatural types are:

Holotype

– A

holotype

is the one specimen or illustration used by the author, or designated by the author as the nomenclatural type. As long as a

holotype

is extant, it fixes the application of the name concerned.

2.

Isotype

-

An

isotype

is any duplicate of the

holotype

; it is always a specimen.

Slide31

3

.

Lectotype

– It is a specimen selected from the original material to serve as the type when no

holotype

was designated or if it becomes missing.

4.

Syntype

– A

syntype

is any one of two or more specimens cited by the original author when no

holotype

was designated.

5.

Neotype

– It is a specimen selected to serve as the type as long as all of the material on which the name of the

taxon

was based is missi

ng.Slide32

6.

Paratype: A

paratype

is a specimen cited with the original description other than the

holotype

or

syntype

.

7.Topotype

: It refers to the specimen collected from the same locality. Slide33

8.

Epitype

-

An

epitype

is a specimen or illustration selected to serve as an interpretative type when the

holotype

,

lectotype

, or previously designated

neotype

, or all original material associated with a validly published name, is demonstrably ambiguous and cannot be critically identified for purposes of the precise application of the name of a

taxon

. When an

epitype

is designated, the

holotype

,

lectotype

, or

neotype

that the

epitype

supports must be explicitly cited Slide34

EFFECTIVE AND VALID PUBLICATION

1)

Name must be effectively published

2) Name must be published in the correct form, properly Latinized with the correct rank ending.

3) Name must be published with a Latin description or diagnosis or with a reference to such. [Vernacular description typically included].

4) Nomenclatural type must be indicated (for genus and below).Slide35

AUTHOR CITATION

Joint authors -

If only two, both should be cited, e.g. Smith & Jones, or Smith

et

Jones, if more than two then Smith

et al

.

2. Name proposal -

S

ometimes one author proposes but doesn't validly publish the name him/herself. In this case the one who proposed it is listed first followed by

ex

and the author who validly published it.

Ex

means validly published by. For example,.

Arenaria

rossii

R.Br

.

ex

Richards. 1823.Slide36

3.

Publication in

anothers

work

-

Sometimes one person supplies the new name for publication in

anothers

work, e.g. many floras. He/she should get credit so cited as Smith in Jones, or if shortened Smith.

4.Abbreviated names:

Usually the names are cited in abbreviated forms but never underlined or italicized e.g.,

Vitex

Linn.,

V .

trifolia

Linn. etc.Slide37

5.Double Citation:

If a genus or

taxon

of lower rank is altered in rank or position, but retains its name or epithet, the name of the author who first published the name or epithet (

basionym

) must be cited in parenthesis

folowed

by the name of author who effected the change

e.g.,

Leucaena

latisiliqua

(Linn.) Gillis (1974)..

Basionym

:

Mimosa

latisiliqua

.Slide38

RULE OF PRIORITY

Law of Priority

says that if a genus or species has been accidentally given two names, only the earlier one is valid.  The later name becomes a "junior synonym”.

Polygala

L.(1753)

,

Poligalia

Neck.(1768),

Polygaloides

Agosti

(1770).Slide39

REJECTION OF NAMES

1. Synonym

-

a rejected name due to misapplication or difference in taxonomic judgment.

2.

Basionym

- a specific epithet or

infraspecific

epithet that has priority and is retained when transferred to a new or different

taxon

, e.g.

Arnica

cordifolia

Hook. if transferred to

Senecio

by Smith becomes

Senecio

cordifolia

(Hook.) Smith. The type specimen for

Senecio

cordifolia

is actually that of

Arnica

cordifolia

.Slide40

3. Homonym

- one of two or more identical names based on different types, only one of which can be legitimate i.e. identical names can not be applied to different

taxa

.

4.

Tautonym

- an illegitimate binomial in which the generic name and specific epithet are the same, e.g. if transfer

Arnica

cordifolia

Hook. to the genus

Cordifolia

would make

Cordifolia

cordifolia

(Hook.)Slide41

5. Autonym

- an automatically created name for

infrageneric

or

infraspecific

taxa

, e.g.

Arnica

subgenus

Arnica

or

Arnica

cordifolia

Hook. subspecies

cordifolia

. Not

genuina

or

typicus

.

6.

Nomen

nudum

-

It is a name that does not fulfill the criteria set by ICBN.Slide42

RETENTION OF NAMES

OfTaxa

which are divided

When a genus/species is divided into two or more genera/spp. The original name must be retained for the type species.

E.g.,

Lychnis

dioica

was divided by Miller into 2 species which were named as

L.

dioica

L. emend Mill. And

L. alba

Miller.Slide43

RETENTION OF NAMES

OfTaxa

on Transference

If a species is transferred to another genus without change of rank, its original name must be retained if a species with that name does not exist in other genus. The name of original author is bracketed followed by the name of second author. For example,

Hydrocotyle

asiatica

L. when transferred to genus

Centella

was named as

Centella

asiatica

(Linn.) Urban.Slide44

CHOICE OF NAMES

Following are the criteria for the choice of name of a

taxon

:

When the

taxon

rank is changed, for e.g., a species becomes a genus, the earliest legitimate name in its new rank is its correct name.

When 2 or more

taxa

of the same rank are united into one, e.g., two or more genera are united , the oldest legitimate name of these

taxa

should be retained as the name of united

taxon

.Slide45

TAXONOMY AS A SYNTHETIC DISCIPLINE

Taxonomy provides a classification based on evolutionary relationships. But the goal of attaining a truly natural system of classification remains unfulfilled. So ,it is essential to have a comprehensive knowledge of the

taxa

from various aspects and various branches of botany. Therefore ,various aspects of botany like anatomy, embryology,

phyto

-chemistry and the newly developed techniques of molecular biology and new aspects of taxonomy i.e. numerical taxonomy are include under taxonomy and thus, taxonomy has now become a synthetic discipline.

Thank you