spike with unisexual flowers/catkin occurs in

Options

A. mulberry
B. grass
C. wheat
D. callistemon

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the type of inflorescence that has unisexual flowers and is referred to as a "catkin" or "spike."

2. **Defining Catkin**: A catkin is a type of inflorescence that is characterized by a long, thin, and pendulous (hanging down) structure. It typically bears unisexual flowers, meaning that the flowers are either male or female, but not both.

3. **Characteristics of Catkin**:
- The peduncle (the stalk that supports the flower) of a catkin is long and weak.
- The flowers are borne in a socile arrangement, meaning they are closely grouped together.
- Catkins are a type of racemose inflorescence, which means they have a branching structure.

4. **Examples of Catkin**: One of the common examples of a plant that produces catkins is the mulberry.

5. **Analyzing Other Options**:
- Grass typically has spikelets, which are a different type of inflorescence.
- Wheat forms spikes, which are also different from catkins.
- Calistemon produces clusters of small flowers arranged in a linear fashion, not catkins.

6. **Conclusion**: Based on the characteristics of catkins and the examples provided, the correct answer to the question is that the spike with unisexual flowers/catkin occurs in the mulberry.

**Final Answer**: The spike with unisexual flowers/catkin occurs in **mulberry**.

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