When the fruit develops from a spike or catkin inflorescence, it is known as

Options

A. syconus
B. sorosis
C. caryopsis
D. hesperidium

Answer

To answer the question "When the fruit develops from a spike or catkin inflorescence, it is known as," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Inflorescence Types**:
- A spike is a type of inflorescence where flowers are attached directly to a central stem without any stalks.
- A catkin is a flowering spike with many small flowers, often seen in trees like willows and oaks.

2. **Identify the Fruit Types**:
- Fruits can develop from various types of inflorescences, and they can be classified into different categories based on their origin.

3. **Recognize Composite Fruits**:
- When fruits develop from multiple flowers of an inflorescence, they are referred to as composite or multiple fruits.

4. **Specific Types of Composite Fruits**:
- The question specifically asks about fruits that develop from spike or catkin inflorescences. The type of fruit that arises from these specific inflorescences is known as **sorosis**.

5. **Eliminate Incorrect Options**:
- **Caryopsis**: This is a type of fruit where the pericarp is fused with the seed coat (like in grains).
- **Hesperidium**: This is a type of berry with a leathery rind (like citrus fruits).
- **Cyconus**: This fruit develops from a hypanthodium type of inflorescence (like in figs).

6. **Conclusion**:
- Therefore, the correct answer to the question is **Psoriasis**, as it refers to the fruit that develops from spike or catkin inflorescence.

### Final Answer:
The fruit that develops from a spike or catkin inflorescence is known as **Psoriasis**.