198 



MANUAL OF POISONOUS PLANTS 



germ tubes are male and produce only male spores, others are female and produce only 

 female spores in the germ sporangium. The sporophyte as well as the gametophyte, there- 

 fore is unisexual. 



"Raggi," used in the manufacture of Arrack, contains Mucor Orysae 

 (Rhisopus) which transforms rice starch into dextrose, the latter being then 

 fermented by yeasts forms blackish brown sporangia and has a pear-shaped 

 columella. Mucor Rouxii of Calmette is commonly grown in China, where it is 

 found on rice husks and is made from these into Chinese yeast. It changes rice 

 starch into sugar and has been used to some extent for manufacture of alco- 

 holic drinks. 



M. racemosus, common in decaying fruit, produces alcoholic fermentation. 

 Mucor fusiger is parasitic on species of Collybia; M. Melittophtorus was found 



Fig. 41. Common Black Mould (Mucor stolonifer or Rhizopus nigricans). 1. Sporangia 



and method of spreading by stolons. 2. Same, showing rhizoids, conidiophore, columella, 



sporangium and spore. 3. Zygospore, showing method of conjugation. 4. Zygospore 

 germinating; k, conidiophore. 



in the stomachs of bees; M. nigricans was found by Neumann (1892) and later 

 by Artanet (1893) in the eye of poultry but Barthelat does not consider it 

 pathogenic. 



Mucor corymbifer, F. Cohn. 



Delicate, white mycelium spreading over the surface of the substratum; 



conidiophores appressed, spreading: branched sporangia in umbellate clusters, 



the lower sporangia smaller than the upper, the latter 70 p diameter; wall 



