126 MORPHOLOGY AND LIFE HISTORY 



throughout? Are cross-walls anywhere present? 

 If so, describe their location. 



2. Is the sporangium borne on the tip of the sporangio- 

 phore, or at one side? Are its contents separated 

 from those of the sporangiophore? If so, how? 

 Compare, on this point, young and old sporangia. 

 Is there more than one sporangium on a sporangio- 

 phore? Within the wall of the sporangium observe 

 the central columella, surrounded by the spores 

 Describe the shape of the columella. Are the 

 spores numerous or few within one sporangium? 

 Look for cases where the wall of the sporangium 

 has ruptured, and the spores are mostly scattered, 

 leaving the columella naked. 



3. Ilustrate by drawings all features observed under 

 G, i and 2. Make the sporangium at least 20 mm. 

 in diameter. 



4. Describe the shape, relative size, color, and surface 

 markings (if any) of the spores. 



H . Sexual Reproduction: 



NOTE. For this study Sporodinia may be substituted, 

 as it more readily yields suitable material. 



1. Find conjugating branches. Describe their shape. 



2. Find mature conjugating branches with the end 

 contents cut off to form gametes. The remainder 

 of the branch is now called a suspensor. 



3. Find, on still more mature material, the gametes 

 fused. What is the resulting structure called? 

 Describe its appearance. If the material is suitable, 

 descibe the germination of this stucture. 



4. Illustrate, with a drawing, all features observed 

 under H. Make the suspensors at least 25 mm. 

 long, and other structures in proportion. 



