The incorrect statement among the following is:

Options

A. Phyllotaxy is whorled in Alstonia.
B. Ovaries are half superior in rose, peach and plum.
C. Ovules are borne on central axis in axile placentation.
D. Placenta is the site of attachment of gynoecium in flower.

Answer

To solve the question regarding which statement is incorrect, we will analyze each of the four statements provided.

### Step-by-Step Solution:

1. **Understanding Filotaxy**:
- The first statement mentions that "Filotaxi is rolled in Elstonia."
- Filotaxy refers to the arrangement of leaves on a stem.
- Rolled phyllotaxy means that more than two leaves arise from a single node, which is indeed seen in plants like Alstonia.
- **Conclusion**: This statement is correct.

2. **Analyzing Ovaries in Rosaceae Family**:
- The second statement claims that "ovaries are half superior in rose, peach, and plum."
- All three plants (rose, peach, plum) belong to the Rosaceae family and they actually exhibit a half inferior ovary, not half superior.
- **Conclusion**: This statement is incorrect.

3. **Examining Ovule Placement**:
- The third statement states that "ovules are born on central axis and axial presentation."
- In axial presentation, ovules are indeed attached to the placenta that develops on the central axis of the ovary.
- **Conclusion**: This statement is correct.

4. **Understanding Placenta in Flowers**:
- The fourth statement mentions that "placenta is the site of attachment of gynoecium in flower."
- The placenta is indeed the tissue in the carpel that bears the ovules, and it is associated with the gynoecium.
- **Conclusion**: This statement is also correct.

### Final Answer:
After analyzing all four statements, we conclude that the incorrect statement is:
- **Option 2: Ovaries are half superior in rose, peach, and plum.** (This is incorrect as they are half inferior.)