Select an incorrect statement.

Options

A. Leaves originate from shoot apical meristems and are arranged in an acropetal order.
B. In monocotyledons, the leaf base expands into a sheath covering the stem partially or wholly.
C. In some leguminous plants the petiole may become swollen, which is called the pulvinus.
D. A typical leaf consists of three main parts.

Answer

To solve the question of selecting the incorrect statement regarding the morphology of flowering plants, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1**: "Leaves originate from shoot apical meristem and arranged in acropetal order."
- **Analysis**: This statement is correct. Leaves do originate from the shoot apical meristem, and they are arranged in an acropetal order, meaning that the younger leaves are at the top and the older leaves are at the bottom.

2. **Statement 2**: "In monocotyledons, the leaf base expands into a sheet covering the stem partially or wholly."
- **Analysis**: This statement is also correct. In monocots, the leaf base does expand to form a sheath that can cover the stem either partially or completely.

3. **Statement 3**: "In leguminous plants, a petiole may be swollen, which is called pulvinous."
- **Analysis**: This statement is incorrect. In leguminous plants, it is the leaf base that swells, not the petiole. The swollen leaf base is referred to as pulvinous, not the petiole.

4. **Statement 4**: "The typical leaf consists of three main parts."
- **Analysis**: This statement is correct. A typical leaf consists of three main parts: the leaf base, the petiole, and the lamina (leaf blade).

### Conclusion:
The incorrect statement is **Statement 3**: "In leguminous plants, a petiole may be swollen, which is called pulvinous."

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