Select the correct option w.r.t. plants bearing ovules which are borne on central axis and lack septa

Options

A. Agremone and mango
B. Dianthus and primrose
C. Tomato and lemon
D. Primrose and marigold

Answer

To solve the question regarding plants that bear ovules on a central axis and lack septa, we will analyze the options provided and identify the correct one based on the type of placentation.

### Step-by-Step Solution:

1. **Understanding the Question**:
The question asks for plants that have ovules borne on a central axis and lack septa. This refers to a specific type of placentation known as "free central placentation."

2. **Analyzing the Options**:
- **Option 1: Argemone and Mango**
- **Argemone**: This plant has parietal placentation.
- **Mango**: This plant also has a fleshy fruit with a central stone, indicating parietal placentation.
- **Conclusion**: This option is incorrect as both plants do not exhibit free central placentation.

- **Option 2: Dianthus and Primrose**
- **Dianthus**: This plant is known to have free central placentation.
- **Primrose**: This plant also exhibits free central placentation.
- **Conclusion**: This option is correct as both plants have ovules borne on a central axis and lack septa.

- **Option 3: Tomato and Lemon**
- **Tomato**: This plant has axial placentation.
- **Lemon**: This plant also has axial placentation.
- **Conclusion**: This option is incorrect as both plants do not have free central placentation.

- **Option 4: Primrose and Marigold**
- **Primrose**: As established, this plant has free central placentation.
- **Marigold**: This plant has basal placentation.
- **Conclusion**: This option is incorrect because Marigold does not have free central placentation.

3. **Final Conclusion**:
After analyzing all options, the only correct option that fits the criteria of having ovules borne on a central axis and lacking septa is **Option 2: Dianthus and Primrose**.

### Final Answer:
The correct option is **Option 2: Dianthus and Primrose**.