Phylum: Ascomycota Family: Mycosphaerellaceae
Mycosphaerella tassiana (Pers.) Link
One of the commonest fungal plant pathogens, known from a host of herbaceous plants and many man-made materials. When looked at on mass it appears olive-green which is a pigment of the conidia
References:
Ellis & Ellis (1997) Microfungi on Land Plants
Ellis & Ellis (1998 enlarged edition) Microfungi on Miscellaneous Substrates: An Identification Handbook