endospore (noun, ascospore term,spore morphology term, pl. endospores; variant spellings: sl. endosporium, pl. endosporia; sl. corium, pl. coria) – the innermost ascospore wall layer; differentiating from the proper spore wall towards the inside of the spore, usually thin and inconspicuous, but in some spores responsible for distinct endospore swellings and septal or spore wall thickenings; Related terms: polarilocular; mischoblastiomorphic; Physciaceae-spore. This is a: part of spore.