MUCOR STOLONIFER. 57 



4. From the lower ends of some hyphae the root-like branches 

 (rhizoids) which penetrate the food material. 



5. The granular protoplasm, in some places densely filling 

 the hyphae. 



6. Draw. 



II. REPRODUCTIVE STRUCTURES. Observe: 



1. The sporangia, in which are blackish masses of spores. 



2. Stages in the development of sporangia, showing: 



a. The tip of an aerial hypha beginning to become swollen. 1 



b. This swollen tip separated from the hypha by means of 

 a transverse wall. 



c. Young sporangia containing immature masses of spores, 

 grayish in color. 



d. Mature sporangia with ripe masses of spores. 



e. The broken sporangium, the swollen tip of the spo- 

 rangiophore (columella), now bulged up into the spo- 

 rangium, and the free spores. 



3 Draw. 



4. Make a rough estimate of the number of spores in a 

 sporangium, and count the number of sporangia in one 

 mount. 



With material that is known to show sex-organs 2 observe : 



5. Branches that have their tips greatly enlarged and grow- 

 ing toward one another. 



6. Such branches whose ends have become cut off by trans- 

 verse walls, and are in contact. 



7. The process of union (conjugation) of these end cells. 



1 Care must be taken not to mistake the swollen columella (see e) 

 which supported an old sporangium, for early stages in the develop- 

 ment of a young sporangium. A columella usually bears a scar which 

 shows where the old sporangium wall was attached. 



2 Unless there is assurance that the material will show sexual repro- 

 duction, no time should be consumed with this part of the study. See 

 text-books for descriptions. 



