Identify the wrongly matched pair.

Options

A. Free central placentation - Dianthus
B. Polyadelphous stamens - Citrus
C. Bilateral symmetry of flowers - Brassica
D. Standard petal of papillionaceous corolla - Vexillum

Answer

To solve the question of identifying the wrongly matched pair, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Placentation**: Arrangement of placenta in the ovary of a flower.
- **Bilateral Symmetry**: A flower that can be divided into two mirror-image halves.
- **Actinomorphic**: A flower that can be divided into symmetrical halves in multiple planes.

2. **Evaluate Each Option**:
- **Option 1: Free Central Placentation** - This type of placentation is indeed found in plants like *Dianthus*. Therefore, this statement is **correct**.

- **Option 2: Polyadelphous Stamen** - This refers to stamens that are fused in groups. Citrus plants are known to have polyadelphous stamens. Thus, this statement is also **correct**.

- **Option 3: Bilateral Symmetry of Flowers in Brassicaceae** - The Brassicaceae family, which includes plants like mustard, typically has actinomorphic flowers, meaning they exhibit radial symmetry, not bilateral symmetry. Therefore, this statement is **incorrect**.

- **Option 4: Standard Petal of Papillonaceous Corolla is Vexillum** - In a papilionaceous flower (like that of the pea family), the standard petal is indeed referred to as vexillum. Hence, this statement is **correct**.

3. **Identify the Wrongly Matched Pair**:
- Based on the evaluations, the third option regarding the bilateral symmetry of flowers in Brassicaceae is the only incorrect statement. Thus, the wrongly matched pair is **Option 3**.

### Final Answer:
The wrongly matched pair is **Option 3: Bilateral symmetry of flowers in Brassicaceae**.