MARCHANTTA POLYMORPHA 97 



(s) Describe the under surface. Note the fringed 

 membranes (perichaetium) . 



(t) Illustrate by drawings all structures observed 



under (p)-(s). 

 Microscopic Characters: 



(u) Study and describe, with drawings (5 cm. in 

 diameter), the structure of the stalk of an 

 archegoniophore as seen in cross-section. Com- 

 pare this with the antheridiophore (F, (/?), P- 



95)- 



(v) Using prepared slides, study longitudinal sec- 

 tions of the receptacle passing through one of 

 its arms. If fresh or preserved material is at 

 hand in sufficient quantity, the study may be 

 made from material "teased out" on the slide. 



(w) Study the tissues of the receptacle. Is there an 

 epidermis? Stomata? Describe (a) the tis- 

 sues just beneath the surface layer of cells; 

 (6) those more deeply seated. 



(x) Observe the flask-shaped archegonia hang- 

 ing from the lower surface of the receptacle. 

 Can you distinguish two regions venter and 

 neck. Note the passage, or neck-canal, leading 

 from the venter through the neck, and opening 

 at the summit. How many cells thick is the 

 wall of the archegonium? Compare with the 

 archegonia of mosses and ferns. 



(y) Surrounding a mature archegonium observe the 

 section of a cup-like structure, the perigynium. 



(z) Within the venter of an archegonium just 

 matured observe a single-celled ovum, or egg. 



(aa) Make drawings illustrating all features shown 

 under ()-(z), and preserve the mounted 

 section for subsequent study. 



