Q. Merits and Demerits of system classification?
Merits
The merits of this system\are as under:
• Careful observation and original description of the genera from living specimens or from herbarium sheets form a fine taxonomic judgement and set a standard for generic description.
• The system is easy to work out and most suitable for all practical purposes or in other words it is quite easy to identify the plants up to family level with the help of this system.
• The geographical distribution of most of the genera included in the system is given.
• Up to date and authentic information is given in the system. Further, Royal Botanic Garden, Kew, is keeping it up to date by the publication of Index Kewensis regularly at the intervals of 5 years.
• Although the system is not phylogenetic, but the position of Ranales (as the starting order of the system) is according to the modern concept of evolution.
• The position of Monocots after Dicots is also logical and in accordance with the modern ,concept of evolutionary trends.
Demerits
There are several demerits or shortcomings of the system namely:
The position-of Gymnosperrnae in, between Dicots and Monocots knot at all logical and appropriate.
The establishment and demarcation of Polypetalae and gamopetalae natural groups creates confusion in some cases. For example, certain members of Cucurbitaceae have gamopetalous conditions but in this system Cucurbitaceae has been placed in Polypetalae. In the treatment of Gamopetalae, Asteraceae, the highest evolved family has been placed in the beginning of the group and thus the position of Asteraceae is not at all justified according to modern evolutionary trends.
• The consideration of Monochlamydeae as a separate and reduced group is not logical because by doing so the closely related families such as Chenopodiaceae could not be placed near Caryophyllaceae.
• Similarly, the inclusion of Orchidaceae in Microspermae, the starting series of Monocot is not in accordance with the recent evolutionary trends. The family Orchidaceae is considered as one of the highest families in Monocots and so it should not be placed as the starting family.