21. These fungi form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus . 22. The two cells from both the protoperithecium and conidium fuse, yet their nuclei remain separate until ascus formation has occurred. 23. The mushroom has a pale yellow or brown thimble-shaped �m, and the presence of only two spores per ascus . 24. The spores are made in structures called operculum a lid that is opened when spores are to be released from the ascus . 25. Perithecial, ascus and ascospore characters in the fruiting bodies are the key identification characteristics of " O . sinensis ". 26. One further mitotic division leads to four " A " and four " a " nuclei in each ascus . 27. The tip of the crozier fuses with the penultimate cell while walling itself off from the ascus by the formation of a septum. 28. These nuclei migrate into a side branch growing from the base of the ascus that repeats the ascus-crozier formation innumerable times. 29. These nuclei migrate into a side branch growing from the base of the ascus that repeats the ascus -crozier formation innumerable times. 30. The spore-bearing cells, the operculum, a lid that is opened when spores are to be released from the ascus .
