SUMMARY
A new pathogenic species, Aspergillus phialiseptus, based on three isolates from clinical specimens is described. The species belongs to the Aspergillus fumigatus series and is characterized by conidial heads with uniseriate but septate phialides bearing short chains of subglobose to pyriform, smooth to finely roughened conidia. When the last conidium in a chain is liberated, a terminal fragment of the phialide remains attached. Strains of A. phialiseptus and A. fumigatus appear to be equally pathogenic in mice.