The present study aimed to recognize the microscopic characteristics of black aspergilli species which exhibit similar characteristics on culture media. Forty eight black aspergilli isolates were obtained from clinical wastes and purified using single spore technique on six different culture media. The ultrastructure of fungal conidiophore and spores was detected by using Scanning Electron Microscope (SEM). The fungal isolates were identified within five species included A. niger, A. tubingensis, Aspergillus section Nigri, A. violaceofuscus, A. neoniger. Besides, two isolates identified as Aspergillus sp. strain no. 39, Aspergillus sp. strain no. 53 appear as new strains based on the structure of conidiophore and spores. The fungi species have similar culture characteristics. However, SEM observation demonstrated that they have quite different conidiophore and spores morphology. The study revealed that the microstructure of the fungal spores and conidiophores plays an important role in the identification of fungi species based on the phenotypic method.
