CHAPTER XX. 



FUNGI: MUCOR AND SAPROLEGNIA. 



Mucor. 



275. In the chapter on growth, and in our study of proto- 

 plasm, we have become familiar with the vegetative condition of 

 mucor. We now wish to learn how the plant multiplies and re- 

 produces itself. For this study we may take one of the mucors. 

 Any one of several species will answer. This plant may be grown 

 by placing partially decayed fruits, lemons, or oranges, from which 

 the greater part of the juice has been removed, in a moist cham- 

 ber ; or often it occurs on animal excrement when placed under 

 similar conditions. In growing the mucor in this way we are 

 likely to obtain Mucor mucedo, or another plant sometimes 

 known as Mucor stolonifer, or Rhizopus nigricans, which is illus- 

 trated in fig. 132. This latter one is sometimes very injurious to 

 stored fruits or vegetables, especially sweet potatoes or rutaba- 

 gas. Fig. 131 is from a photograph of this fungus on a banana. 



276. Asexual reproduction. — On the decaying surface of the 

 vegetable matter where the mucor is growing there will be seen 

 numerous small rounded bodies borne on very slender stalks. 

 These heads contain the gonidia, and if we sow some of them in 

 nutrient gelatine or agar in a Petrie dish the material can be 

 taken out very readily for examination under the microscope. 

 Or we may place glass slips close to the growing fungus in the 

 moist chamber, so that the fungus will develop on them, though 

 cultures in a nutrient medium are much better. Or we mav take 

 the material directly from the substance on which it is growing. 



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