Chif merit of Bentham and Hooker's classification is that :-

Options

A. It is a system mostly based on evolutionary concepts
B. It is a natural systems of classification of all groups of plants
C. The description of the taxa are based on actual observation of the specimen
D. It also includes the phylogenetic aspects

Answer

**Step-by-Step Solution:**

1. **Understanding the Classification System**: The Bentham and Hooker classification system is a natural system of classification that was developed by two English botanists, George Bentham and Sir Joseph Dalton Hooker. This system is significant in the field of botany.

2. **Evolutionary Concept**: One of the chief merits of this classification is that it is largely based on evolutionary concepts. This means that it takes into account the evolutionary relationships among different plant groups.

3. **Natural Classification**: The Bentham and Hooker system is considered a natural classification because it organizes plants based on their natural relationships rather than arbitrary characteristics. This makes it more reflective of the actual diversity in the plant kingdom.

4. **Observation-Based Taxonomy**: A key feature of this classification is that the descriptions of taxa (groups of organisms) are based on actual observations of specimens. This empirical approach ensures that the classification is grounded in reality and not just theoretical.

5. **Phylogenetic Aspect**: The classification also includes phylogenetic aspects, which means it considers the evolutionary history and relationships among plants. This adds depth to the classification system and helps in understanding the lineage of different plant groups.

6. **Accurate and Reliable Descriptions**: The descriptions provided in this classification are noted for their accuracy and reliability. They are based on direct observations, making it easier to classify plants up to the family level.

7. **Conclusion**: Therefore, the chief merit of Bentham and Hooker's classification is that the descriptions of taxa are based on actual observation of specimens, which enhances the reliability and accuracy of the classification.

**Final Answer**: The chief merit of Bentham and Hooker's classification is that the descriptions of taxa are based on actual observation of specimens.

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