Armen Takhtajan, an influential botanist, developed a comprehensive system of classification for flowering plants, first published in 1942. His system, based on multiple phyletic principles, categorizes angiosperms into Magnoliopsida (dicots) and Liliopsida (monocots), further divided into subclasses and emphasizing evolutionary relationships. Some criticisms of his classification include its derivation of monocots and the splitting of related taxa.

1. SEMINOR BY
K.DIWAKAR
1ST YEAR MSC BOTANY
RAYALASEEMA UNIVERSITY
KURNOOL,ANDHRA PRADESH

2.  ARMEN TAKHTAJAN WAS
BORN IN 1910
 WAS DIED IN 2009
 Armen Takhtajan who is the
head of the department of
higher plants at the komarov
botanical institute in
Leningrad,Russia, presented a
system of classification,which
was first published in a very
preliminary form in 1942
ARMEN TAKHTAJAN

3.  TAKHTAJAN was inspired by Hailier’s attempt
to create a synthetic evolutionary
classification of flowering plants based on
Darwinian philosophy and his approach is
very much similar to that of Cronquist

4.  Takhtajan’s system of classification is
basically of Bessey-Hallier tradition which
considerd all evidences from different fields
including
morphological,anatomical,embryological,cytol
ogical,palynological,paleobotanical,chemical
and ultrastructural evidences while classifying
Angiosperms

5.  Takhtajan divided the
Magnoliophyta(Angiosperms) into two
classes-Magnoliopsida(Dicotyledons) and
Liliopsida(Monocotyledonds),of which
Magnoliopsida is considered primitive and
Liliopsida to have been derived from
Magnoliales under Magnoloiopsida .
 The two classes have been further divided in
to 10 subclasses, 7 under the Magnoliopsida
and 3 under Liliopsida(1980),which are as
follows

6. Class: Magnoliopsida
(Dicots)
Class: Liliopsida
(Monocots)
Manolidae Alismatidae
Ranunculidae Liliidae
Hamamelididae Arecidae
Caryophyllidae
Dilleniidae
Rosidae
Asteridae

7.  However according to Takhtajan’s system of
classification,1997,the two classes have been
divided into 15 sub classes, 11 under the
Magnoliopsida and 5 under Liliopsida, which
are as follows:

9.  Among the sub classes,Takhtajan considered
Magnoliidae to be the most primitive,forming
basal group from which all other subclasses
have been derived.
 Among the Magnoliopsida,he considered the
Asteridae the most advanced.
 The three subclasses under
Liliopsida(Aalismatadae,Liliidae and Arecidae)
are considered to the primitive than the other
sub classes of Magnoliopsida,and have been
derived from Magnoliiodae.
 Among Anigiosperms,the Winteraceae family
is most primitive and Poaceae the most
advanced

10. Takhtajan’s system is based on 67 phyletic
principles.some of the important criteria used
by him to evaluate the relative degree of
advancement of flowering planta are as
follows:
 Woody plants are primitive than herbaceous
plants
 Deciduous woody plants are considered
evolved from ever green plants
 Xylem fiber evolved from tracheids to
libriform fibers,through fiber tracheids
 Trilacunar or penta lacunar nodes are
primitive to unilacunar nodes

11.  Alternate leaf arrangement is primitive while
parallel venation is most advanced
 Stomata with subsidary cells are primitive
than those lacking subsidary cells
 Cymose inflorescence is primitive than
racemose
 Flowes with an indefinite or variable number
of floral parts are primitive
 Pollen with unsculptured exine is primitive to
sculptured pollen
 Apocarpous gynoecium is primitive

12.  Bitegmic ovules are primitive than unitegmic
ovules,while anatropous ovule is most
primitive
 8-nucleated polygonum type female
gametophyte is most primitive
 Mesogamic and Chalazogamic conditions
have evolved from Porogamic conditions
 Among fruits many seeded follicle is most
primitive

13.  The Dicots(Magnoliopsida)has been
disscussed prior to Monocots(Liliopsida)
 The familes are small homogenous units
made up of closely related genera
 The Dicots begin with Magnoliales,which is
highly satisfactory as Magnoiliales are
universally considered to be the most
primitive living Angiosperms

14.  Among Monocots, the Alismatales, which are
considered to be the most primitive living
Monocots,have been placed at the starting
point,which is satisfactory
 Engler and Prantl’s division of Dicots into two
traditinal groups- Archichlamydae and
Metachlamydae,has been abolished in this
system
 Problems such as monophyly are polyphyly,
interrelationhips of Dicots and Monocots,
primitive position of Magnoliales, the
secondary nature of anemophilous families
with reduced unisexual flowers, etc.have been
satisfactorily settled.

15.  The main objection to Takhtajan’s system is
his derivation of Monocotyledons from the
stocks of ancestral to the Nymphaeales
 The extremely narrowly defined taxa in this
system has resulted in the unwarranted
splitting of related groups