Study following statements regarding the preparation of herbarium sheets.
(i) Plant should be collected in flowering stage.
(ii) Every detail regarding the plant such as locality, ecological conditions, vegetative and floral characters, etc. should be noted.
(iii) Plants are evenly pressed by unfolding all the plant parts between blotting papers (or newspapers) with the help of plant pressers.
(iv) Blotting papers need not be changed until the plant gets dried.
(v) After drying, the plant specimen is carefully mounted/pasted on the herbarium sheets.
(vi) The herbarium sheet is labelled on the lower right hand corner representing the number of plant specimen, data of collection, etc.
Which of the above statements is/are not correct ?

Options

A. (i) only
B. (iv) only
C. (i) and (iv)
D. (iii) and (iv)

Explanation

To determine which statements regarding the preparation of herbarium sheets are not correct, let's analyze each statement step by step:

1. **Statement (i)**: "Plant should be collected in flowering stage."
- **Analysis**: This statement is generally correct. Collecting plants in their flowering stage is ideal as it provides more information about the plant's reproductive structures, which are crucial for identification.

2. **Statement (ii)**: "Every detail regarding the plant such as locality, ecological conditions, vegetative and floral characters, etc. should be noted."
- **Analysis**: This statement is correct. Detailed notes are essential for proper identification and understanding of the plant's habitat and characteristics.

3. **Statement (iii)**: "Plants are evenly pressed by unfolding all the plant parts between blotting papers (or newspapers) with the help of plant pressers."
- **Analysis**: This statement is also correct. Proper pressing and unfolding of plant parts is necessary to ensure they dry evenly and maintain their structure.

4. **Statement (iv)**: "Blotting papers need not be changed until the plant gets dried."
- **Analysis**: This statement is incorrect. Blotting papers should be changed frequently to prevent mold and ensure that the plant dries properly. If the blotting paper becomes saturated, it should be replaced with dry paper.

5. **Statement (v)**: "After drying, the plant specimen is carefully mounted/pasted on the herbarium sheets."
- **Analysis**: This statement is correct. Once dried, the specimens are mounted on herbarium sheets for preservation and study.

6. **Statement (vi)**: "The herbarium sheet is labelled on the lower right-hand corner representing the number of plant specimen, data of collection, etc."
- **Analysis**: This statement is correct. Proper labeling is crucial for identification and record-keeping.

### Conclusion:
The only statement that is not correct is **Statement (iv)**: "Blotting papers need not be changed until the plant gets dried."

### Final Answer:
- **Incorrect Statement**: (iv)

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