Which of the following statements is incorrect about the class Deuteromycetes?

Options

A. They reporduce only by asexual spores (conidia).
B. Mycelium in these fungi is branched and septate.
C. They have only parasitic forms.
D. Examples of these fungi are Altermaria, Colletotrichum and Trichoderma.

Explanation

To determine which statement about the class Deuteromycetes is incorrect, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Deuteromycetes**:
- Deuteromycetes, also known as "imperfect fungi," are characterized by their asexual reproduction primarily through conidia (asexual spores).
- They typically have a well-developed, branched, and septate mycelium.

2. **Analyzing the Statements**:
- **Statement 1**: "They reproduce only by the asexual spores that are conidia."
- This statement is **true**. Deuteromycetes primarily reproduce asexually through conidia.

- **Statement 2**: "Mycelium in these fungi is branched and septate."
- This statement is also **true**. Deuteromycetes have branched and septate mycelium.

- **Statement 3**: "They have only parasitic form."
- This statement is **incorrect**. Deuteromycetes can exist in various forms, including saprophytic and mutualistic forms, not just parasitic.

- **Statement 4**: "Examples of fungi are Ultramarnia, Colectotrichum, and Trichoderma."
- This statement is **true**. These are indeed examples of fungi classified under Deuteromycetes.

3. **Conclusion**:
- The incorrect statement about Deuteromycetes is: "They have only parasitic form."

### Final Answer:
The incorrect statement about the class Deuteromycetes is: **"They have only parasitic form."**