SYSTEMS OF CLASSIFICATION
Plant classification system can be divided into five kinds.
- Artificial System
- Mechanical System
- Natural System
- Phylogenetic System
- Phenetic System
The following trends have been followed in the development of a system of plant classification shown in the figure which depicts the development of various kinds of classification form taxa to the system.
(period ancient ca. 300bc to ca. 1580 ad) circa = about
The classification systems developed at this period was based on merely the habit (tree, shrub, under a shrub, climber, herb, runners, evergreen, cultivated, wild, annual, biennial, perennial, etc) of plants.
Eg Theophrastus (The Grand Father of Modern Botany)
John Ray; Andrea Caesalpinus, Caspar Bauhin
(period ca 1580 to ca 1760 ad)
The classification systems developed at this period was based on the habit as well as organs of fructification such as position, locule, number, and seed number.
Eg Carl Linnaeus (1753)
(period ca 1760 to 1880 ad)
these systems were based on the overall morphological or external resemblances of the plants
Eg Bentham and Hooker’s system; A. P. De Candolle
(period ca 1880 to 1958 ad)
These systems of classification were based on the overall characters known to that time and emphasis were laid down to depict the Phylogenetic (evolutionary) relationship of plants
Eg Adolf Engler and Karl Prantal; John Hutchinson
(period ca 1958 onward ad)
These systems of classification were based on the overall characters known to its own time and emphasis were laid down to depict the natural relationship rather than strictly to laid consideration on phylogenetic (evolutionary) relationship of plants. The concept and development of the phonetic system of the classification are based on the principles of Numerical Taxonomy (comparative scientific procedure: a procedure that involves comparing a large number of characteristics of one organism with the same characteristics of other using statistical methods, and computer technology).
Eg Marvin Takhtajan (1980); Arthur Cronquist’s system and Dr. Rolf Dahlgren’s system (1983)
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