Rhizopus oryzae (Rhizopus arrhizus)
A very rapid-growing fungus that produces a brownish-gray colony within four days, when incubated at 25oC (77oF). It has worldwide distribution but is found primarily in the tropical and subtropical areas. It has been isolated from soil, salt marshes, mines, caves, bat guano, bird feathers, fresh and salt water, plants, and foodstuffs. Rarely, it can be an opportunistic human pathogen causing zygomycosis.