210 THE BIOLOGY OF THE PLANT 



I. The sexual reproductive organs, or gametangia. 



On mature specimens look for the curved an- 

 theridia and the oval obgonia. On what part 

 of the plant are they found? Does the same 

 plant bear both organs ? How many of each do 

 you find on one filament ? How are they situated 

 with regard to each other ? What differences do 

 you find in shape, size, and color ? 



a. The antheridium or male organ. — What is its 

 shape ? Compare its diameter with that of the 

 filament. Note the pedicel or stalk — its shape 

 and structure. What does it contain ? How is it 

 connected to the filament ? Does its cavity com- 

 municate with that of the filament ? With that 

 of the antheridium proper ? Look for anthero- 

 zoids or sperm-cells in the antheridium. What 

 is their shape ? Color ? Arrangement in the an- 

 theridium ? Examine a number of specimens to 

 find antheridia in various stages of development. 

 If any are found, make sketches of them. Look 

 for empty antheridia. In what respects do they 

 differ from the other ? Look for antheridia from 

 which the antherozoids are escaping, and study 

 the details of the process — how the antherozoids 

 are set free, their motions, and general behavior 

 after leaving the antheridium. If antherozoids 

 are found, apply iodine in order to see their cilia. 

 How many have they 1 



I. The oogonium or female organ. — Compare 

 with the antheridium in shape, size, color, and 

 mode of attachment to the filament. Is its cavity 

 continuous with that of the filament? Does it 

 have a pedicel ? Endeavor to trace the develop- 



