True elaters and gemmae are concerned with:-

Options

A. Riccia
B. Marchantia
C. Anthoceros
D. Notothylus

Answer

To answer the question regarding True elaters and gemmae, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding True Elaters**:
- True elaters are specialized cells found in certain plants, particularly in the group of liverworts. They are hygroscopic, meaning they can absorb moisture from the environment, and they can change shape in response to humidity. This ability helps in the dispersal of spores.

2. **Understanding Gemmae**:
- Gemmae are small, asexual reproductive structures found in some liverworts. They can detach from the parent plant and grow into a new individual, allowing for vegetative reproduction.

3. **Identifying the Plant Group**:
- The question asks which plant group True elaters and gemmae are associated with. The options provided are Ricia, Markantia, Anthoceros, and Notothilus.

4. **Analyzing the Options**:
- **Ricia**: This is a genus of liverworts, but it is not specifically known for true elaters.
- **Markantia**: This is a genus of liverworts that is well-known for having true elaters and gemmae.
- **Anthoceros**: This is a genus of hornworts, which do not have true elaters.
- **Notothilus**: This is not a recognized group in the context of true elaters and gemmae.

5. **Conclusion**:
- Based on the information, the correct answer is **Markantia**, as it is the group that contains both true elaters and gemmae.

### Final Answer:
True elaters and gemmae are concerned with **Markantia**.

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