Synonymy: Rhizopus oryzae
Morphological Description: Colonies are very fast growing, about 5-8 mm high, with some tendency to collapse, white cottony at first becoming brownish grey to blackish-grey depending on the amount of sporulation. Sporangiophores up to 1500 µm in length and 18 µm in width, smooth-walled, non-septate, simple or branched, arising from stolons opposite rhizoids usually in groups of three or more. Sporangia are globose, often with a flattened base, greyish black, powdery in appearance, up to 175 µm in diameter and many spored. Columellae and apophysis together are globose, subglobose or oval, up to 130 µm in height collapsing to an umbrella-like form after spore release. Sporangiospores are angular, subglobose to ellipsoidal, with striations on the surface, and up to 8 µm in length. No growth at 45C; good growth at 40C.
Culture of Rhizopus arrhizus.
Sporangiophores, rhizoids and sporangia of R. arrhizus.
Sporangium with collapsed columella and sporangiospores of R. arrhizus.