Choose the incorrect statement about Ascomycetes.

Options

A. Mycelium is branched and septate
B. Sexual spores are produced endogenously
C. They have sac like structure in which karyogamy takes place
D. Reduction division occurs in fruiting bodies and forms conidia

Answer

To solve the question of identifying the incorrect statement about Ascomycetes, we will analyze each of the provided statements step by step.

### Step-by-Step Solution:

1. **Understanding Mycelium**:
- The first statement mentions that "Mycelium is branched and septate."
- Mycelium in Ascomycetes is indeed branched and composed of septate hyphae. This statement is **correct**.

2. **Sexual Spores Production**:
- The second statement states, "Sexual spores are produced endogenously."
- In Ascomycetes, sexual spores are called ascospores, and they are produced endogenously within sac-like structures called asci. This statement is also **correct**.

3. **Karyogamy Process**:
- The third statement claims, "They have sac-like structures in which karyogamy takes place."
- Karyogamy, which is the fusion of nuclei, occurs within the asci of Ascomycetes. This statement is **correct**.

4. **Reduction Division and Conidia**:
- The fourth statement says, "Reduction division occurs in fruiting bodies and form conidia."
- This statement is misleading. While reduction division (meiosis) does occur in the formation of ascospores (sexual spores) within the asci, conidia are asexual spores produced by mitosis, not through reduction division. Therefore, this statement is **incorrect**.

### Conclusion:
The incorrect statement about Ascomycetes is the fourth one: "Reduction division occurs in fruiting bodies and form conidia."