Classicula sinensis, a new species of basidiomycetous aquatic hyphomycetes from southwest China

Classiculasinensis, isolated from decaying leaves from Mozigou, Chongqing Municipality, China, is described as a new species. The new species is a member of basidiomycetous aquatic hyphomycetes which represent a small proportion of all aquatic hyphomycetes. This species falls within the genus Classicula (Classiculaceae, Pucciniomycotina) and is closely related to C.fluitans, based on multiple gene sequence analyses. Morphologically, it is characterised by the apical, hyaline, obclavate or navicular conidia with several hair-like lateral appendages and by its holoblastic and monoblastic conidiogenesis, with a flat un-thickened conidiogenous locus. Clamp connections and haustorial branches were often observed in culture.

Ultrastructure of conidial and microconidial ontogeny of Marssonina species pathogenic to poplars

Conidial and microconidial ontogeny of Marssonina brunnea, M. castagnei, and M. populi was annellidic. The primary conidium and microconidium developed holoblastically and a new slightly higher conidiogenous locus was formed with each percurrent vegetative proliferation through the annellophore apex. Delimiting septa were perforate with Woronin bodies and electron-dense septal pore plugs were observed in the bases of seceded conidia and microconidia.

Fine structure of conidiogenesis in the mosquito pathogen Culicinomyces clavosporus (Deuteromycotina)

Conidiogenesis in Culicinomyces clavosporus Couch, Romney, and Rao (Deuteromycotina) is initiated with the growth of conidiogenous cells from vegetative hyphae. Formation of the primary conidium itself begins with a conidial initial which grows through the bilaminar wall at the tip of the conidiogenous cell, wall remnants of the conidiogenous cell often collapsing to form a collarette at the base of conidia. This factor, in addition to the fixed conidiogenous locus, shows that the conidiogenous cell is a phialide. As the conidial initial enlarges, a bilaminar well is synthesized around the cell, and cytoplasmic organelles migrate through the neck of the phialide into the initial. Once the conidium is mature, a septum is formed across the open neck of the phialide and two organelles (dense-core vesicles and autophagosomes), unique to conidia, become evident. The mode of development is enteroblastic–phialidic; Culicinomyces clavosporus is placed therefore in section IVB of the Hughes–Tubaki–Barron classification scheme described by B. Kendrick for the Deuteromycotina.

The ultrastructure of conidium ontogeny in Pestalotiopsis neglecta

Electron microscopy has been used to study conidium ontogeny of Pestalotiopsis neglecta, an annellidic coelomycete, to compare it with previously studied phialidic fungi. It was found that phialidic fungi produce a multiplicity of conidia from a fixed conidiogenous locus within the conidiophore, but annellidic fungi produce conidia individually from progressively different, usually higher, loci within the conidiophore. With the exception of the primary phialidic conidium, both types of organism produce conidia enteroblastically.

Conidiogenesis in Termitaria snyderi (Fungi Imperfecti)

Termitaria snyderi Thaxter forms small discoid lesions on the exoskeleton of different species of termites. Its conidiogenesis has been studied by light and electron microscopy. The phialides are oriented parallel in a closely packed sporodochium. The conidia are produced endogenously in basipetal succession from a fixed conidiogenous locus and are liberated when the tip is broken off the phialide as a result of the force applied by the formation of new conidia. The area of the phialide beyond the locus forms a tubular collarette. The conidium initial buds out at the locus and after it has received its organelles and reached a certain size it is delimited by a centripetally growing transverse septum. The region of the growing septum has many vesicles which may be involved in cross wall synthesis. Conidia are cylindrical, uninucleate, and double-walled. They have mitochondria, endoplasmic reticulum (ER), conspicuous lipid droplets, and vacuoles. Each conidiophore has long mitochondria, elongate nuclei, and much endoplasmic reticulum. The plasmalemma of the conidiophore is highly convoluted.

Fine structure of conidiogenesis in the holoblastic, sympodial Tritirachium roseum

Electron microscopy of conidiogenesis in Tritirachium roseum was done on material fixed in glutaraldehyde followed by OsO4. The walls of conidiogenous cells, though pigmented, lacked well-defined differential electron-transmission layers. Conidial initials developed without the appearance of a rupture in the conidiogenous cell wall, i.e., development was holoblastic. Each successively produced conidiogenous locus developed below and to one side of the previously formed conidium, and the fertile region of the conidiogenous cell elongated in a geniculate pattern. After each conidial initial reached full size, it was delimited by a centripetally developing septum, which increased in thickness, became double, and split during conidial secession. The distal half of a split septum formed the conidial base; the proximal half remained as part of the conidiogenous cell wall. Upon conidial secession, basal frills on conidia, and secession scars on conidiogenous cells were especially conspicuous.