Differentiate between caudex and culm stem.

Explanation

### Step-by-Step Solution

1. **Definition of Caudex Stem**:
- A caudex stem is characterized as an unbranched stem that is erect, cylindrical, and stout.
- It is typically marked with scars and remnants of fallen leaves.

2. **Examples of Caudex Stem**:
- A common example of a caudex stem can be found in palm trees. The structure of the palm tree's stem fits the description of a caudex.
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