cleistocarp(n = noun.plant) cleistothecium - closed spore-bearing structure of some fungi (especially Aspergillaceae and Erysiphaceae) from which spores are released only by decay or disintegration;
the closed spore-bearing structure of some fungi (especially Aspergillaceae and Eurysiphaceae) from which spores are released only by decay or disintegration; -- called also cleistothecium. [WordNet 1.5]