Aspergillus niger

Aspergillus niger on three media: CBS, a malt extract recipe; CYA, Czapek Yeast extract agar; CZ, Czapek Solution Agar after 7 days at 25°C. The sporing heads are often brown when viewed under a dissecting microscope (and more so on certain media), though they appear more or less black en masse. The metullae can become very long, sometimes with a transverse wall and the spores can be almost smooth to very rough and about 4µ. The black pigment seems to be associated with the roughness of the wall which is laid down as irregular thickenings. [Photos taken by John Frank, FAO Consultant]