Which of the following are not a group of green algae ?

Options

A. Chlamydomonas, Volvox
B. Ulothrix, Spirogyra
C. Gelidium, Gracilaria
D. Chlamydomonas and Chara

Answer

To determine which of the following options are not a group of green algae, we need to identify the characteristics of green algae and the specific examples provided in the question.

### Step-by-Step Solution:

1. **Understand Green Algae**: Green algae are primarily classified under the division Chlorophyta. They contain chlorophyll A and chlorophyll B, which give them their green color. Common examples include Chlamydomonas, Spirogyra, Volvox, and Chara.

2. **Analyze the Options**:
- **Chlamydomonas**: This is a well-known genus of green algae. It belongs to the group of green algae (Chlorophyta).
- **Volvox**: Another genus of green algae, known for its spherical colonies. It also belongs to Chlorophyta.
- **Eulothrix**: This is also classified as green algae, belonging to the Chlorophyta division.
- **Spirogyra**: This is a filamentous green algae, which is part of the green algae group.
- **Gelidium**: This is not a green algae; it is classified as red algae (Rhodophyta).
- **Glossaryria**: This is also not a green algae; it is classified as red algae (Rhodophyta).
- **Chara**: This is a genus of green algae and belongs to the Chlorophyta division.

3. **Identify Non-Green Algae**: From the analysis, we can see that Gelidium and Glossaryria do not belong to the group of green algae.

4. **Final Answer**: The options that are not a group of green algae are **Gelidium and Glossaryria**.