Trimerous flowers occur in

Options

A. Monocots
B. Dicots
C. Gymnosperms
D. All the above.

Answer

**Step-by-Step Solution:**

1. **Understanding Trimerous Flowers**:
- Trimerous flowers are characterized by having floral parts in multiples of three. This means that the petals, sepals, stamens, and carpels are typically found in groups of three.

2. **Identifying Flower Types**:
- The question asks in which group of plants trimerous flowers occur. The options provided are monocots, dicots, gymnosperms, and all of the above.

3. **Analyzing Monocots**:
- Monocots are a group of flowering plants that typically exhibit trimerous flowers. Examples include lilies, orchids, and grasses, where the floral parts are indeed in multiples of three.

4. **Analyzing Dicots**:
- Dicots, on the other hand, usually have floral parts in multiples of four or five, known as tetramerous or pentamerous flowers. Therefore, they do not produce trimerous flowers.

5. **Analyzing Gymnosperms**:
- Gymnosperms do not produce flowers at all; instead, they produce naked seeds. Since they lack flowers, they cannot be classified as having trimerous flowers.

6. **Conclusion**:
- Based on the analysis, the only group that consistently exhibits trimerous flowers is monocots. Therefore, the correct answer is that trimerous flowers occur in monocots.

**Final Answer**: Trimerous flowers occur in monocots.

---