The reproductive structure in ascomycetes that contains spores is called an ascus.

Here's a bit more information:

* Asci are sac-like structures that develop within the fruiting body of an ascomycete fungus.

* Ascospores, the spores produced by ascomycetes, are formed inside the ascus.

* Asci can contain a variety of numbers of ascospores, usually 4 or 8, depending on the species.

Let me know if you'd like to know more about ascomycetes or their reproductive cycle!