n 1  cap  :  a genus of fungi of the family Mucoraceae that have columellate hemispherical aerial sporangia formed in fascicles anchored to the substrate and tufts of rhizoids or root hyphae connected by stolons and that include a common bread mold (R. nigricans) and several forms found in phycomycoses of some mammals including humans  2  :  any fungus of the genus Rhizopus .
 
 
 
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