316 THE BIOLOGY OF THE PLA1?T 



erine and examine under the low power. "What 

 is the shape of the section? JSTote in the re- 

 ceptacle flask-shaped, dark-colored masses, the 

 antheridia. Of what tissues is the receptacle 

 composed? Compare with the thallus. Do 

 you find scales, rhizoids, etc., on the section? 

 If so, to what part are they confined ? Exam- 

 ine under the high power. Note that each an- 

 theridium is contained in a well-defined cavity. 

 What is the shape of an antheridium? Does 

 it have a stalk ? What is the structure of the 

 wall of the antheridium ? Do the cells contain 

 chlorophyll ? How are the cells arranged ? 

 Can you naake out its contents ? Do you find 

 unicellular papillEe, the paraphyses, at the 

 base of the antheridium? How does the an- 

 theridium communicate with the exterior ? 

 Do the antheridia vary in size and develop- 

 ment in different parts of your section? If 

 so, Avhere are the oldest? Draw the section. 

 If living material containing mature antheri- 

 dia be used, some of the sections will probably 

 show escaping antherozoids. If so, study 

 their structure and movements. Compare 

 them with the antherozoids of Chara and 

 Fucus. Draw. 



Make a horizontal section of the surface of 

 the antheridial receptacle, and examine under 

 the high power. Do you find that it has 

 the same structure as the surface of the thal- 

 lus? ISTote the smaller openings or pores, 

 leading to the antheridial cavities. Do these 

 pores differ in structure from the stomata? 

 Draw. 



