Which of the following is a phaeophycean alga?

Options

A. Gelidium
B. Polysiphonia
C. Porphyra
D. Laminaria

Answer

To determine which of the given options is a phaeophycean alga, we will analyze each option based on their classification.

### Step-by-step Solution:

1. **Identify the Options**: The options provided are:
- A) Gallidium
- B) Polysiphonia
- C) Porphyra
- D) Laminaria

2. **Classify Each Alga**:
- **Gallidium**: This alga belongs to the group of red algae (Rhodophyta).
- **Polysiphonia**: This is also a member of the red algae (Rhodophyta).
- **Porphyra**: This is yet another example of red algae (Rhodophyta).
- **Laminaria**: This alga is classified under brown algae (Phaeophyceae).

3. **Determine the Correct Answer**: Since the question asks for a phaeophycean alga, we focus on the classification of Laminaria. It is known for being a brown seaweed and is characterized by its leathery texture and larger size compared to the other options.

4. **Conclusion**: The correct answer to the question "Which of the following is a phaeophycean alga?" is **D) Laminaria**.