Ultrastructure of hyphomycetes. Conidium ontogeny in Peziza ostracoderma

Light microscope and electron microscope studies of conidium ontogeny in the Chromelosporium state of Peziza ostracoderma Korf show that the solitary blastoconidia are produced synchronously on swollen elongate divergent ampullae through a process involving denticle development at localized 'soft spots' in the ampulla wall followed by a 'ballooning' of the denticle tip to form the conidium. Cytoplasm and nuclei move from the ampullae into the developing conidia. The occurrence and position of lomasomes in denticles and conidia support the assumption that these multivesicular bodies are associated with wall synthesis. The taxonomic and nomenclatural history of the Chromelosporium state of Peziza ostracoderma is reviewed.