Closed fruiting bodies in fungi, especially ascomycetes, that contain asci with spores but don't open spontaneously.
From Greek 'kleistos' (closed) and 'theke' (case), plural form 'clistothecia.' Technical mycological terminology.
These are the ultimate mystery containers of the fungal world—fungi went through the effort of packaging spores in elaborate cases but then sealed them permanently, trusting decay or animal action to spread them.
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