Aspergillus fungus. Coloured scanning electron micrograph (SEM) of the fungus Aspergillus fumigatus. The fungus is made up of fungal threads (hyphae, grey) with conidiophores (fruiting bodies, brown) at the tip. The conidiophores are made up of chains of conidia (spores), which are dispersed on the wind. Inhalation of spores by people with a weakened respiratory system, for example asthmatics or those with cystic fibrosis, leads to an allergic reaction known as aspergillosis. A. fumigatus usually grows on decomposing organic matter. Magnification: x510 when printed at 10cm wide.