Engler and Prantl classification system: History, Outline of Classification, Merit and Demerits of classification II With MCQ II Botany-Biology

 Engler and Prant system of classification

Type of system of classification: Phylogenetic system of classification 

History background: 

Heinrich Gustav Adolf Engler (1844-1930), Professor of Botany, University of Berlin, Germany, proposed a phylogenetic system of classification in a book entitled Syllabus (1892). 

Soon after, Engler in collaboration with Karl Anton Prantl another German Botanist, published a monumental work entitled “Die-Natürlichen Pflanzenfamilien” (1887-1915) having 23volumes, Hans Melchior published the revised (13th) edition of Syllabus in 1964 with a number of modifications in this system.

 

Outline of the classification:

The Englar and Prantl system often considered as phylogenetic one was not strictly phylogenetically in modern sense as it was an arrangement in linear sequence starting with simplest group in order of increasing complexity.

The work includes key and description of all known genera of plants.

As a whole 303 families of flowering plants were recognized in this system. 

According to this system the families were arranged in accordance to their increasing complexity of fruit, flower and seed development.

In their system of classification-Plant Kingdom has been divided, into XIII Divisions in the original classification. In the original classification, Divisions I to XI deal with Bacteria, different types of Algae and Fungi.

The XIIth Division was named Embryophyta Asiphonogama (plants having an embryo but no pollen tube) and included the Bryophytes and Pteridophytes.

The XIIIth Division was named Embryophyta Siphonogama (plants having an embryo and a pollen tube) It is divided into 2 sub-divisions based on the naked and enclosed ovules, that is

i) Gymnospermae (Plants with naked ovules)

ii) Angiospermae (Plants with enclosed ovules)

The sub-division Gymnospermae has been divided into 7 orders, the starting one being Cycadofilicales, the most primitive one where as the ending order is Gnetales, an advanced group of Gymnosperms.

The sub-division Angiospermae has been split into two

i) Class Monocotyledonae, and     ii) Class Dicotyledonae

The Monocotyledons are further divided into 11 Orders and 45 Families. The first or the starting Order is Pandanales which possesses naked, unisexual flowers with Typhaceae as the starting family. The last order is Microspermae with Orchidaceae as the last family

The Dicotyledons are divided into 2 subclasses namely:

i) Archichlamydeae, and

ii) Metachlamydeae/Sympetalae

Archichlamydeae has 33 Orders and 186 Families. The first or the starting order being Verticillatae and Casuarinaceae as the starting family . The last Order being Umbelliflorae with Cornaceae as the last family.

Sympetalae which is also named as Metachlamydeae has 11 Orders in all with 52 Families. The first or the starting Order being Ericales .The last or ending order of Sympetalae is Campanulales with Asteraceae or Compositae as the last or ending family and that is very rightly placed because this family is considered as the highest evolved family among Dicots.

MERITS OF THE SYSTEM OF CLASSIFICATION

Although, Engler himself did not consider the system as a true phylogenetic one but the arrangement of Order and Families in the system is mostly according to evolutionary tendencies.

The system was first to incorporate idea of organic evolution.

The system covers the entire plant kingdom ranging from Bacteria, Algae, Fungi, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms.

The position of Gymnosperms before Angiosperms is very accurate and is in perfect accordance to the modern concept of evolution.

Gymnosperms are treated seperately .

The terms Cohort and natural order are replaced by Order and Family respectively.

Anatomical data were taken into consideration in this system of classification for the first time.

According to this system the large unnatural families are debolished, Monochlamydeae has been completely abolished and its families have been placed in Archichlamydeae.

Consideration of gamopetalous condition over polypetalous condition is in line with current phenetic system of classification.

The families with inferior ovary have been treated in last in both Archichlamydeae and Sympetalae .The advancement is marked from hypogyny to complete epigyny.

Compositae in dicots and orchidaceae in monocots are considered as advanced with inferior ovary.

Closely related families like Liliaceae and Amaryllidaceae has been placed under same order Lilifloreae.

The system considered orchids to be highly evolved than grasses.

DEMERITS OF THE SYSTEM OF CLASSIFICATION

There are some shortcomings or demerits of the system. The important demerits are as under:

The concept of primitive flower (unisexual, naked, catkin) in accordance with the system is against the modern concept of evolution.

Monocots are regarded more primitive than Dicots. This concept is not in agreement with modern concept of evolution.

The system is not of much practical utility

Angiosperms are considered of polyphyletic origin but most of recent evidences points toward monophyletic origin.

Amalgamation of Apetalous families to form Archichlamydeae is not desirable as it has resulted in the formation of an unmanageable large group with 33 Orders and 186 families.

Aracae are included in order spathiflora which is placed before lilliflorae but now aracaea in monocot are believed tohave evolved from Lilliaceae .

Helobiae placed after Pandanales are now considered as primitive group.

Oder Ranales is primitive . In this system Ranales are placed much lower among monocots .

Derviation of central placentation from parietal or axile placentation is illogical

Consideration of Bisexual flower from Unisexual flowers doesnot match with modern concept.

The acceptance of derivation of dichlamydous flower from monochlamydous flower is objectionable.

Lilliaceae was considered as large unnatural family which now has been splitted into several small families.

Amalgamation of Apetalous families to form Archichlamydeae is not desirable as it has resulted in the formation of an unmanageable large group with 33 Orders and 186 families.

Derivation of bisexual flower from unisexual flower is also objectionable.

Derivation of entomophilous flower from anemophilous flower is objectionable.

QUESTION PRACTICE

Who author the book Die-Natürlichen Pflanzenfamilien? (HPPSC PGT Biology)

Thorne

Cronquist

Englar and Prantl

Thaktajan

Which of the following is a demerit of the 'Engler and Prantl' system of classification?

(1) Dicotyledons are placed before monocotyledons.

(2) Dicotyledons are placed after monocotyledons.

(3) Gymnosperms are placed among dicotyledons.

(4) Gymnosperms are-placed between dicotyledons and monocotyledons.

COMMENT DOWN THE ANSWER