Practice question

Conidium defined as asexual external spore not enclosed by sporangial wall or sac, formed via mitosis. Originates exogenously on conidiophore surface via blastic growth from conidiogenous cell, detached at base leaving scar. Zoospore motile but formed inside zoosporangium with wall, sporangiospore clustered within sporangium membrane requiring rupture, ascospore enclosed inside ascus requiring rupture. External position without protective sac allows immediate wind dispersal, characteristic of Aspergillus, Penicillium and dermatophytes. Hence conidium matches description of externally formed spore lacking protective sac, distinguishing it from endogenous spores retaining sporangial envelope surrounding them.