The development of ascospores of Hansenula anomala (Hansen) H. & P. Syd. was studied by electron microscopy. Within the young ascus, a double membrane develops around each of the haploid nuclei enclosing mitochondria, oil vacuoles, and endoplasmic reticulum as well. Two ascospore wall layers are deposited within the intercisternal space. The initial wall layer develops centripetally from the extremities of the base, then around the crown of the hat-shaped spore. In many spores, this initial wall is thin or incomplete around the upper portion of the crown. The second wall layer is less electron dense and is formed adjacent to and immediately within the initial layer. At maturity of the spores, no organelles remain in the epiplasm.

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Budding and fine structure were examined in two compatible haploid strains of Tremella mesenterica. Budding is initiated at one pole; successive buds are developed at the initial site and at any subsequently formed sites. The budding process appears to combine features found in apiculate and non-apiculate ascosporogenous yeasts, and in Sporobolomyces and Rhodotorula. The fine structure observed suggests that new wall material might be deposited within cells as each successive bud is formed. No differences were observed in either structure or budding of the two mating strains examined.

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.