Phylum：Zygomycota　>>　Class： Zygomycetes　>>　 Order： Mucorales 
   
 
　BCRC Number： NO BCRC Number!  
   
　Scientific Name： Rhizomucor miehei
 
   
   
　Author：

Rhizomucor miehei (Cooney and Emerson) Schipper, Stud. Mycol. 17: 58. 1978.
   
 
 
 
 
　Description： Colonies on PDA growing well, reaching all plates in 3 days at 40°C, white at first, turning to Pale Mouse Gray*, Olive-Gray*; reverse Marguerite Yellow*. At 50°C, white, margin irregularly undulate; reverse Empire Yellow* to Pale Yellow* or Marguerite Yellow. Vegetative hyphae have rhizoids but developed poorly, hyaline, not limited under the sporangiophores. Sporangiophores smooth, some have crystals, grown from any site of vegetative mycelia, branched loosely in sympodial, with or without septa. Sporangia are globose, subglobose, Pale Yellow-Green*, turning to pale brown, brown at maturity, 23-31 × 22-34 μm. At 30°C, sporangia slightly larger, 28-35.2 μm in diam. Columellae smooth, globose, subglobose, ellipsoid, rarely pyriform-ellipsoid or umbrella-shaped, 13.4-30.7 × l2.2-36.5 μm. Sporangiospores smooth, globose, subglobose, ellipsoid or irregular in shape, pale green, 3.8-5.1 μm in diam. Zygospores homothallic, globose, subglobose, first pale grayish green then to yellowish brown or dark brown, 25.6-42.9 × 27.5-44.8 μm. Suspensors equal, conical.
 
 
 
 
 
　Specimens：

null
 
 
 
　Habitat： Field soil of Taitung area of Taiwan (TAI-14T510).
 
 
 
　Distribution：

Japan, Taiwan, USA
 
 
 
　References：

Chen, GY and Chen, ZC. 1990; Schipper, MAA. 1978-2.
   
   
   
　Provided：

K. Y. Chen
 
 
　Note： Temperature: Growth and sporulation only at 25-50°C; at 20°C, extremely slow growth; at 40°C, abundant sporangia and zygospores; .at 50°C, form sporangia sparsely. Zygospores are formed at 30°C, 35°C and 40°C. The formation of zygospore is very similar to that of Rhizopus stolonifer (Ehrenb: Fr.) Vuill reported by Ho (1988). Two opposite zygophores contact, fuse and swell, accordingly their shape changed from cylindrical to globose. The suspensor also swell following the mating of gametangia. The outer wall of zygospores eventually cracking, the warts protruding and continuousely enlarge untill the shape of warts changing to blunt spines (Plate 2-F). According to Schipper and Stalper (1978), some strains of Rhizomucor pusillus and Rh. miehei are homothallic. Therefore the homothallism could not be used as the key character for distinguishing two species. Instead, the zygospore size should be regarded as a key character in distinguishing two species. In our previous report, Rh. pusillus was isolated from the San-Tzu area of Taiwan (Chen and Chen, 1988) but no zygospore was observed. The two species of Rhizomucor isolated from Taiwan are thus distinguished mainly by branching pattern of sporangiophores, sporangium size, and slightly different requirement of growth temperature. Although this species isolated from Taiwan can grow poorly at 20℃, it is still considered to be a thermophilic fungus.