Which of the following statement is incorrect ?

Options

A. In Australian acacia , the petioles expand, become green and synthesize food.
B. If more than two leaves arise at a node and form a whorl , it is called whorled , as in mustard.
C. In palmately compound leaves , the leaflets are attached at a common point , i.e., at the petiole , as in silk cotton .
D. Leaves of dicotyledonous plants generally possess reticulate venation , while parallel venation is the characteristic of most monocotyledons.

Answer

To determine which statement is incorrect, we need to analyze each of the provided statements regarding plant biology.

1. **Statement 1**: In Australian Acacia, the petioles expand, become green, and synthesize food.
- This statement is **correct**. In Australian Acacia, the petioles can indeed become green and perform photosynthesis, similar to leaves.

2. **Statement 2**: If more than two leaves arise at a node forming a whorl, it is called whorled as in mustard.
- This statement is **incorrect**. The correct example for whorled leaves is not mustard; it is typically found in plants like Alstroemeria or Nerium. Mustard generally has alternate or opposite leaf arrangements.

3. **Statement 3**: In palmately compound leaves, the leaflets are attached at a common point, therefore are the petiole as in silk cotton.
- This statement is **correct**. In palmately compound leaves, the leaflets do indeed attach at a single point on the petiole.

4. **Statement 4**: Leaves of Dicotyledons generally possess reticular venation while parallel venation is the characteristic of the Monocotyledons.
- This statement is **correct**. Dicotyledons typically exhibit reticulate venation, while monocotyledons show parallel venation.

Based on the analysis above, the **incorrect statement** is **Statement 2**.

### Final Answer:
The incorrect statement is: **If more than two leaves arise at a node forming a whorl, it is called whorled as in mustard.**