140 PRACTICAL BOTANY. 



been damaged in the process of preparation. For the 

 observations on its structure see below. 



By hardening in alcohol, or by fixing with picric acid, and 

 subsequently treating with staining reagents, it may be 

 demonstrated that numerous nuclei are present in the hyphse 

 of Mucor. 



It has been stated above that the hyphae of Mucor are not 

 septate : this is the case in young cultures, but preparations 

 should also be made from old cultures, after the production of the 

 sporangia : in these numerous septa may be found. 



It has also been stated that the gonidiophores are unbranched : 

 that is so in the large majority of cases, but in old cultures 

 lateral branches may be found arising below the sporangium, and 

 themselves terminated in turn by a sporangium. 



III. Cut off a number of mature sporangia with 

 scissors from the flocculent growth, treating them very 

 gently, so as to avoid damage : mount them in alcohol, 

 and examine them quickly under a low power : 

 observe 



1. The cylindrical gonidiophores, terminated by 



2. The spherical and dark-coloured sporangium, 

 with its dense contents, and its very thin limiting wall, 

 often bearing small radiating projections. 



3. Towards the point of attachment to the stalk a 

 clearer space may be recognised in the contents ; this 

 indicates the position of the columella. 



Add a drop of water, and draw it under the cover- 

 slip with blotting-paper, watching the effect upon the 

 sporangia : as the water gains access to the sporangia, 

 they burst suddenly, and the wall may be torn to frag- 

 ments so minute that it cannot be recognised again. 

 Meanwhile the contents, the swelling of which caused 



