318 THE BIOLOGY OF THE PLANT 



make out the structure of the contents ? How 

 is the neck formed ? How does it compare in 

 length and diameter with the body? Draw 

 a single mature archegonium. Examine the 

 section for younger, unfertilized archegonia. 

 Where do you find them ? Does their position 

 correspond with that of the immature antheri- 

 dia ? Draw several young archegonia to show 

 the various stages of their development. Com- 

 pare the young with the older archegonia. 

 Look on older receptacles for the ripening 

 archegonia, or sporogonia, and study their 

 structure. "What changes have taken place in 

 the perigynium, in the neck, and in the body ? 

 Draw. Crush a living sporogonium and exam- 

 ine the spores and spirally-marked elaters. 

 Mount them without the drop of water and ex- 

 amine, then allow a small drop to flow under 

 the cover, being careful to keep watch of the 

 elaters. What change takes place in them 

 when they are moistened ? Of what use may 

 this be? Draw some of the spores and elaters. 



PHTSIOLOGT 



a. The fertilization of the oosphere. 



H antheridia and archegonia of the proper age 

 be obtained, it will not be difficult to watch cer- 

 tain stages of the process of fertilization. Make 

 vertical sections of the two receptacles, bearing 

 respectively mature antheridia and archegonia, 

 and mount them in the same drop of water. 

 Note the motions of the antherozoids, their jour- 



