Which of the following statements is not correct regarding the class Ascomycetes?

Options

A. Conidia are the asexual spores produced endogenously on conidiophores.
B. Ascospores are the sexual spores produced endogenously in asci.
C. Aspergillus, Neurospora and Claviceps are Ascomycetes fungi.
D. Mycelium is generally branced and septate in Ascomycetes.

Explanation

To determine which statement is not correct regarding the class Ascomycetes, we will analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Understand the Class Ascomycetes**: Ascomycetes, also known as sac fungi, are a group of fungi characterized by the production of ascospores in a sac-like structure called an ascus. They can reproduce both sexually and asexually.

2. **Evaluate the First Statement**:
- **Statement**: "Conidia are asexual spores produced endogenously on the conidiophores."
- **Analysis**: Conidia are indeed asexual spores, but they are produced exogenously, not endogenously. This means they are formed on the surface of specialized structures called conidiophores. Therefore, this statement is incorrect.

3. **Evaluate the Second Statement**:
- **Statement**: "Ascospores are sexual spores produced endogenously in the asci."
- **Analysis**: This statement is correct. Ascospores are indeed sexual spores that develop within the ascus, which is a characteristic feature of Ascomycetes.

4. **Evaluate the Third Statement**:
- **Statement**: "Aspergillus, Neurospora, and Claviceps are Ascomycetes fungi."
- **Analysis**: This statement is also correct. All these genera belong to the class Ascomycetes.

5. **Evaluate the Fourth Statement**:
- **Statement**: "Mycelium is generally branched and septate in Ascomycetes."
- **Analysis**: This statement is correct as well. The mycelium of Ascomycetes is typically branched and contains septa (cross-walls).

6. **Conclusion**: After evaluating all the statements, the first statement about conidia being produced endogenously is the only incorrect statement regarding Ascomycetes.

### Final Answer:
The statement that is not correct regarding the class Ascomycetes is: "Conidia are asexual spores produced endogenously on the conidiophores."

---