A vertically growing thick usually unbranched underground stem with more diameter than length is

Options

A. sucker
B. straggling
C. corm
D. rootstock

Answer

To solve the question "A vertically growing thick usually unbranched underground stem with more diameter than length is," we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Characteristics**: The question describes a stem that is:
- Vertically growing
- Thick
- Usually unbranched
- Underground
- Has more diameter than length

2. **Analyze the Options**: We need to evaluate the provided options based on the characteristics mentioned:
- **Sucker**: This is not a completely underground stem; it is usually sub-aerial, so it does not fit the description.
- **Straggling**: This type of stem is also not suitable as it typically has a length greater than its width.
- **Root Stock**: Similar to straggling, root stocks are usually underground but have a length greater than their diameter, making them incorrect for this question.
- **Corm**: This is a type of underground stem that is thick, usually unbranched, and has a diameter greater than its length. It fits all the characteristics described in the question.

3. **Conclusion**: Based on the analysis, the correct answer is **Corm**.

### Final Answer:
The correct answer is **Corm**.

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