Which of the following does not have an elaborate mechanism of spore dispersal ?

Options

A. Funaria
B. Polytrichum
C. Sphagnum
D. Riccia

Answer

To solve the question "Which of the following does not have an elaborate mechanism of spore dispersal?", we will analyze each of the given options: Finaria, Polytrichum, Sphagnum, and Rissia.

### Step-by-Step Solution:

1. **Identify the Groups**:
- Finaria, Polytrichum, and Sphagnum are all types of mosses.
- Rissia is a type of liverwort.

**Hint**: Group the options based on their classification (mosses vs liverworts).

2. **Understand the Sporophyte Structure**:
- In mosses (Finaria, Polytrichum, Sphagnum), the sporophyte is more developed and contains a capsule where spores are produced in large numbers after meiosis.
- In liverworts (Rissia), the sporophyte is less developed, and the capsule containing spores is embedded in the gametophyte. The number of spores produced is also fewer compared to mosses.

**Hint**: Compare the sporophyte structures of mosses and liverworts.

3. **Examine Spore Dispersal Mechanisms**:
- Mosses have an elaborate mechanism for spore dispersal. They utilize various methods such as wind, water, and even animals to disperse their spores effectively.
- In contrast, liverworts like Rissia have a less developed mechanism for spore dispersal. The spores are fewer in number and the dispersal is not as effective or elaborate.

**Hint**: Look for the effectiveness and complexity of spore dispersal in each group.

4. **Conclusion**:
- Since Rissia (the liverwort) has a less elaborate mechanism for spore dispersal compared to the mosses (Finaria, Polytrichum, Sphagnum), the correct answer to the question is Rissia.

**Hint**: Identify which option stands out due to its simpler structure and mechanism.

### Final Answer:
Rissia does not have an elaborate mechanism of spore dispersal.