THE PLANT GROUPS 107 



b. Archegonia and antlieridia (structure of sex organs). 

 Study sections of plants cut so as to show the form 

 and structure of the sex organs. 



(1) Note in each organ an outer layer and a central 



column of cells. What is the cellular structure 

 of these two groups of cells ? the function of 

 each ? Are these cell groups alike in the female 

 organ, or archegonium, and in the male organ, 

 or antheridium ? If sex organs of different ages 

 are availahle, note the method of liberating sperms 

 and exposing the eggs for fertilization. 



(2) Comparisons. How do the archegonia and the antlie- 



ridia of the liverwort differ from the gametangia 

 (oogonia and antheridia) of alga? and fungi ? Are 

 archegonia and antheridia better adapted for secur- 

 ing the development of gametes and fertilization 

 in amphibious plants like liverworts than the 

 gametangia of algffi and fungi ? Be able to explain. 



(3) Write a brief summary of the structure and adapta- 



tions of the sex organs in liverworts. Indicate 

 also the important distinctions between arche- 

 gonia and antheridia and the gametangia of algse 

 and fungi. 



(4) Draw diagrams illustrating the structure of each. 



Study the structure of the sex organs in the text 

 and label parts of your figures accurately. 



SPOROPIIYTE AXD LIFE HISTORY 



1. Sporophyte. Study sporophytes of Ricciocarpus or other 



liverworts by dissection and in sections. 

 a. Structure. What kinds of tissues and cells are found 

 in the sporophyte that you are examining ? What 

 is the apparent function of the tissues and cells 



