Published online by Cambridge University Press: 01 September 1997
Hyalorhinocladiella and Sporothrix are two common mycelial anamorphs of Ophiostoma that are difficult to distinguish from each other. Sporothrix spp. differ visibly from Hyalorhinocladiella by the presence of denticles on the conidiogenous cells. Graphium and Sporothrix are often synanamorphs of the same Ophiostoma species and the aim of this study was to determine whether a relationship exists between sympodial conidium development in Sporothrix and annellidic development in Graphium. Conidium development was examined in Sporothrix schenckii, Ophiostoma nigrocarpum and Ophiostoma piceae. Using fluorescence microscopy, as well as scanning and transmission electron microscopy, distinct denticles were observed on the conidiogenous cells in Sporothrix spp. In some cases, these conidiogenous cells were reduced, giving them a Hyalorhinocladiella-like appearance. Results of this study suggest that a continuum in patterns of conidium development exists between Sporothrix, Hyalorhinocladiella and Graphium. The linear extent, and the angle of the proliferation stage with reference to the long axis of the conidiogenous cell, appear to determine the form of conidium development.