Practice question

Cleistothecium describes completely closed, spherical to subspherical ascoma lacking any ostiole or natural opening, characteristic of powdery mildews like Podosphaera, Erysiphe and Eurotiales including Aspergillus and Penicillium sexual stages. Peridium membranous composed of interwoven hyphae encloses irregularly scattered globose prototunicate asci each containing ascospores; release occurs only after peridial decay, mechanical cracking or ingestion by arthropods. This closed architecture provides protection in xeric, epiphytic or cleistocarpous niches against desiccation, differing from open cup apothecium, flask perithecium with pore and mushroom-like basidiocarp of basidiomycetes.