In which of the following plants ovules are borne on the central axis of the ovary without septa?

Options

A. China rose, lemon
B. Dianthus, Primrose
C. Pea, bean
D. Mustard, argimone

Answer

To determine which of the following plants has ovules borne on the central axis of the ovary without septa, we need to understand the concept of placentation in flowering plants.

### Step-by-Step Solution:

1. **Understand Placentation**: Placentation refers to the arrangement of ovules within the ovary. Different types of placentation include free central, axile, marginal, and parietal.

2. **Identify Free Central Placentation**: In free central placentation, ovules are attached to a central column (the central axis) within the ovary, and there are no septa (partitions) dividing the ovary into locules.

3. **Evaluate the Options**:
- **China Rose and Lemon**: These plants exhibit axile placentation, where ovules are arranged around a central axis but are separated by septa.
- **Dianthus and Primrose**: These plants show free central placentation, where ovules are borne on the central axis without any septa.
- **Pea and Bean**: These plants have marginal placentation, where ovules are located at the margins of the ovary.
- **Mustard and Argemone**: These plants exhibit parietal placentation, where ovules are attached to the walls of the ovary.

4. **Conclusion**: The only option that describes plants with free central placentation (ovules borne on the central axis without septa) is **Dianthus and Primrose**.

### Final Answer:
**Dianthus and Primrose** are the plants where ovules are borne on the central axis of the ovary without septa.

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