Modern System of Classification

The system of classification is used all types of information i.e. morphology, anatomy, histological, biochemical and DNA analyses. The modern classifications are as follows:

Tackhtazan, Cronquist, Angiosperm Phyllogeny Group (APG) etc.

According to Arther Cronquist, Angiosperm or Magnoliophyta Division is classified into two Classes:

A. Class- ()

B. Class- ()

A. Class Magnoliopsida (Dicotyledon) has six subclasses (S), 63 orders, 315 families, and around 165400 . The class has following subclasses:

S1- Magnoliidae

This subclass contains 8 orders, 39 families and about 11000 species. They are most primitive angiosperms. The major characteristics of the members of Magnoliidae subclass are:

 Many parted well-developed perianth of tepals  Differentiated into sepals and but sometimes apetalous  The stamens are numerous and mature in a centripetal manner

S2-Hamamelidae

This subclass possesses 11 orders, 23 families and about 3400 species, it is the smallest subclass of dicots. The important characteristics of the subclass are:

 The perienth is absent or poorly developed  Many are unisexual  The mature fruit contains single

S3-Caryophyllidae

The subclass Caryophyllidae contains three orders, 14 families and about 11000 species. The subclass has following characteristics:

 Mostly herbaceous mostly succulents or halophytes  Placentation is mostly free central or basal  are tricoplate

S4-

It contains 13 orders, 78 families, and about 24000 species. The important characteristics are  Contain many woody species  Centrifugal maturation of stamens and binucleate

S5-

The subclass has 18 orders, 113 families, and about 60000 species. It is the largest subclass among the .

Characteristics

 The flower has numerous stamens that mature in centripetal sequence.  Polypetalous corolla

S6-

The sub-class Asterdae contains 10 orders, 48 families and about 56000 species. It is the second largest sub-class of dicotyledons.

Characteristics

The stamens are few and alternate with petals

B. Class Liliopsida (monocotyledon) has five subclasses (S)

S1:

The sub-class has 4 orders, 15 families and 500 species. The sub-class has following

Characteristics:

 They are mostly primitive, aquatic or wetland habitats.  Most are apocarpous and have trinucleate pollen

S2: (4 orders, 6 families, and about 6400 species)

 Members of the subclass vary from tiny macroscopic duckweeds to huge woody palms.  About 50% of the species are arborescent  Stomatal subsidiary cells are usually four

S3: Commelinidae (6 orders, 16 families, and about 16200 species)

 Majority of the species are herbaceous  Pollen is either trinucleate or binucleate

S4: (2 orders, 9 families, and about 2800 species) They are mainly tropical

S5: (2 orders, 19 families, and 28000 species)

 They are highly developed for pollination  Majority are terrestrial or epiphytic herb  are generally linear with parallel veined or broad to netted veined

DIVISION : MAGNOLIOPHYTA (Flowering )

CLASS : MAGNOLIOPSIDA (Dicotyledon)

Subclass : Magnoliidae

Order I : Family 1 :Annonaceae

Order II : Nymphiales Family 2 : Nymphiaceae

Subclass : Hamamelidae

Order III : Family 3 :Moraceae Family 4 :Cannabaceae Family 5 : Urticaceae

Order IV : Myricales Family 6 :

Order V : Casuarinales Family 7 :

Subclass : Caryophyllidae

Order VI : Caryophyllalaes Family 8 :Cataceae Family 9 : Amaranthaceae Family 10 : Chenopodiaceae

Subclass : Dilliniidae

Order VII : Family 11 : Theaceae Family 12 : Clusiaceae Order VIII : Family 13 :Malvaceae Family 14 : Malvaceae

Order IX : Family :Cucurbitaceae Family :Caricaceae

Order X : Capparales Family 15 : Brassicaceae Family 16 : Moringaceae

Subclass : Rosidae

Order XI : Family 17 : Rosaceae Order XII : Family 18 : Fabaceae Family 19 : Rutaceae Family 20 : Meliaceae Family 21 : Anacardiaceae Order XIII : Family 22 : Apiaceae Order : Family 23 : Family 24 :Convulaaceae Family 25 :Lamiaceae Order XIV : Family 26 : Asteraceae

CLASS: LILIOPSIDA (Monocotyledon)

Subclass: Arecidae Order XV : Family 27 : Arecaceae Order XVI : Family 28 : Aracae

Subclass: Commelinade Order XVII : Family 29 : Poaceae

Subclass: Zingiberidae Family 30 : Sterlitziaceae Family 31 :Musacae Family 32 : Zingibiracae

Subclass: Liliidae Order XVIII : Family 33 : Order XVIV : Orchidiales Family 34 :Orchidiaceae

Table Differences between Magnoliopsida (Dicotyledon) and Liliopsida (Monocotyledon)

Characters Magnoliopsida Liliopsida (Dicotyledon) (Monocotyledon)

1 Cotyledon Two one 2 Endosperm Absent Present 3 Leaves Reticulated venetation Parallel venetation 4 system Tap root Fibrous 6 Growth form May be herbaceous or woody Mostly herbaceous, few are arborescent 7 Usually arranged in ring form Arranged in scattered form 7 Cambium Present Absent 8 Primary vascular bundle In a ring form Arranged in scattered form

9 Present Absent

10 Floral parts Parts are usually in four or Parts are three or multiple five of three

Angiosperm Phylogenic Group (APG)

The Angiosperm Phylogeny Group, or APG, refers to an informal international group of systematic botanists who came together to try to establish a consensus on the of flowering plants (angiosperms). The term angiosperm is derived from the Greek words angeion and sperma, meaning vessel and seed, respectively. Contrasting to gymnosperms (naked-seeded plants), in which the are usually borne on ovulate cone scales, in angiosperms the seeds are protected in vessel called the carpel, which matures into fruit.The APG system of classification is the first, now obsolete, version of a modern, mostly molecular based system of which was published in 1998.

Member institute of APG 1. Swedish Academy of Sciences 2. Uppsala University; 3. Stockholm University 4. Royal Botanic Gardens, Kew 5. University of Maryland; 6. Cornell University 7. University of Florida 8. Florida Museum of Natural History 9. Harvard University Herbaria 10. University of Missouri-St. Louis and 11. Missouri Botanical Garden

Clade

In the terms of biological systematics, a clade is a single "branch" on the “tree of life. It is a grouping of organisms which have a common ancestor and the grouping is made on the basis of presumed evolutionary history. It is a group of organismssharingfeaturesthatreflect a commonancestor or descent.

Figure Graphical sketch of clade

Clades of Angiosperm

1. Monocots 2. Commelinoids 3. 4. Core eudicots 5. 6. Eurosids I 7. Eurosids II 8. Asterdis 9. Euasterdis I 10. Euasterdis II