LIVEEWOET SIV 



How many points of resemblance in struct- 

 ure can you discover between an antheridial 

 branch and a thallus ? 

 The archegonial branch. — Make sections of 

 the archegonial, and compare them with the 

 sections of the antheridial branch. Do you find 

 any marked differences in shape, size, structure, 

 etc. ? Do you find the same tissues to be pres- 

 ent and similarly arranged? Draw the sec- 

 tions. Kemove one of the arms of the archego- 

 nial receptacle, make transverse sections of it, 

 and compare the structure with that of the 

 stalk. Examine vertical sections, and find on 

 the lower surface of the receptacle the flask- 

 shaped archegonia with elongated necks. JSTo- 

 tice how these are distributed through the sec- 

 tion. Do you find them to be arranged in pairs, 

 with a wing-like down-growth (sections of the 

 perichsetium) on each side? Draw. 



Stu'dy the structure of a single archegonium 

 which has been fertilized. These may usually 

 be distinguished from others by the fact that 

 the lower portion contains a dark-brown mass. 

 Make out the stalk, the body, and the elon- 

 gated neck. "What is the structure of the stalk ? 

 From what does it arise ? Does it resemble the 

 stalk of an antheridium? Surrounding the 

 stalk look for the section of a cup-shaped mass 

 of cells, the perigynium. How much of the 

 archegonium does the perigynium cover? "What 

 is its structure ? What is the shape of the body 

 of the archegonium? "What is the structure 

 of its wall? "What does it contain? Do the 

 contents entirely fill the cavity? Can you 



