which of the following characters are not appplicable to the anantomy of dicot stem.
(a) colenchymatous hypodermis
(b) polyarch xylem
(c) presence of casparian strips on endodermis
(d) open vascular bundle
(e) presence of medullary rays

Options

A. a d and e only
B. b and c only
C. b and e only
D. a, b and c only

Answer

To determine which characters are not applicable to the anatomy of a dicot stem, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Option (a): Collenchymatous hypodermis**
- In dicot stems, the outer layer of the cortex often consists of collenchyma, which provides support. Therefore, this character is applicable to dicot stems.

2. **Option (b): Polyarch xylem**
- Polyarch xylem is characterized by having multiple xylem strands. This is typically not found in dicot stems, which usually have a smaller number of xylem strands (usually 2-4). Thus, this character is not applicable to dicot stems. This is a potential answer.

3. **Option (c): Presence of Casparian strips on endodermis**
- Casparian strips are found in the endodermis of roots, not in stems. Since dicot stems do not have an endodermis with Casparian strips, this character is also not applicable to dicot stems. This is another potential answer.

4. **Option (d): Open vascular bundle**
- Dicot stems typically have open vascular bundles, which contain cambium between xylem and phloem. Therefore, this character is applicable to dicot stems.

5. **Option (e): Presence of medullary rays**
- Medullary rays are present in dicot stems and serve to transport nutrients and water between the pith and the cortex. Thus, this character is applicable to dicot stems.

### Conclusion:
The characters that are not applicable to the anatomy of dicot stems are:
- **(b) Polyarch xylem**
- **(c) Presence of Casparian strips on endodermis**

### Final Answer:
The correct options are (b) and (c).

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