If an ascomycete typically produces 4 spores in each ascus does this mean that division stops at the 4-cell stage or that maybe after the 4th division which should give a final eight spores one of two spores aborts? I am examining a lichenicolous species of Pyrenidium and after many attempts found an ascus with 4 mature, brown spores. This is important for its ID. However when observing numerous asci in the process of development I am given the impression that 8 spores are developing. Each spore is finally tri-septate and so the 4 cell lumina might be contributing to my interpretation of counting 8 spores..