No. of ascospores formed in each ascus of Penicillium is

The correct option is 8.

Penicillium is a genus of fungi belonging to the phylum Ascomycota, commonly known as sac fungi. The characteristic sexual spore-producing structure in these fungi is a sac-like cell called an ascus (plural: asci).

The formation of ascospores inside each ascus follows a specific sequence of nuclear divisions:
1. Karyogamy: Within the young developing ascus, two haploid nuclei fuse to form a single diploid zygote nucleus.
2. Meiosis: This diploid nucleus undergoes meiosis (reduction division) to produce 4 haploid nuclei.
3. Mitosis: Each of the 4 haploid nuclei subsequently undergoes one mitotic division, resulting in a total of 8 haploid nuclei within the ascus.
4. Spore Wall Formation: Cytoplasm and wall material condense around each of the 8 haploid nuclei to form 8 mature, haploid ascospores.

Therefore, a typical ascus of Penicillium contains exactly 8 ascospores.