EXERCISE 80 

 BREAD MOLD 



Materials. The rather coarse cottonlike growth that commonly 

 appears on bread is referred to as bread mold or black mold. It is 

 often not the first mold to appear on bread, but its growth is so 

 vigorous that it soon covers up the others. It may be recognized 

 by its large white heads (sporangia), which soon turn black. (See 

 textbooks, undbr -the heading Rhizopus nigricans, for descriptions.) 

 It "may be' found also in some of the other cultures. If it appears 

 on" tie ,eflk<ti!)/the transparency of the medium will allow the whole 

 plant to be seen. 



Directions for work. Study the plant and its manner of 

 growth with the naked eye and the hand lens. Describe it 

 carefully. Look for it in all the other cultures, including the 

 cultures of bacteria. If it can be found growing on the gelatin 

 or the agar cultures made in Exercise 76, study the distribution 

 of the plant below the surface. 



If the plant has spread from the bread to the surface of the 

 containing dish, as commonly occurs, note how it advances into 

 new territory. 



References 



BERGEN and CALDWELL. Practical Botany, pp. 214-217. 

 BERGEN and CALDWELL. Introduction to Botany, pp. 235-239. 



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