Taxonomy of Angiosperms #Part I# Principles & Practices# 1# Phases of Taxonomy#4th Sem Honours#TU

                 According to Turril (1938) plant classifications are of two types i.e. Alpha Taxonomy &  Omega Taxonomy  which are based on the four "Phases of Taxonomy" (Davis & Heywood, 1963).

                These successive phases are as follows:

(1) Pioneer Phase: 

       The collection of different members of a taxon from the whole world and then provisional identification is the Pioneer Phase or Exploratory Phase.

(2) Consolidation Phase:

       Morphological study of plants first at the field and then in the herbarium is performed ,if a new group/ groups is/are discovered then fully described.

      Thus ,extensive herberium collections and field studies are done to compile a Flora or a Monograph in this phase .

(3) Experimental Phase or Biosystematic Phase:

      In this phase a detailed study of a taxon is done on the basis of both of Pioneer Phase and Consolidation Phase in addition to different studies like those of geographical variations, chemical study, cytogenetic study, physiology, fertility relationship, evolutionary pattern and population studies ,etc.

(4) Encyclopaedic Phase :

       The above said three phases are coordinated and involved to analysed and to  synthesized all the recorded data and  informations to develop a system of plant classification on the basis of hologenic relationships.

       (A) Alpha Taxonomy :  The term "Alpha"was coined by Turril in 1935.  Pioneer Phase and that of Consolidation Phase which are based on morphology  together coordinated  the Alpha Taxonomy , the empirical aproach in Plant Taxonomy(Valentine & Love,1958; Davis & Heywood,1963).

         (B)Omega Taxonomy :

              It represents the Biosystemstic or Experimental Phase in the development of Taxonomy involving detailed Cytology and Genetics (Valentine and Love1958 ).   

    Whereas, according  Heywood both of Biosystemstic Phase & Holotaxonomy are jointly analysed and synthesized to achive Omega Taxonomy.

                              Exercise

(1) Define alpha and omega taxonomy.

                                                      2/2007

(2) Explain the Consolidation, Biosystemstic and Encyclopaedic phases of Taxonomy.                              6/2007