76 COMMON LIVER IVOR T. 



a. The bulbous base : in optical section make out a 

 single layer of cells inclosing a central cavity. 



b. The long neck} 



c. A ring rising up around the base in some cases, 

 the early stage of the perianth. 



d. Draw. 



4. The sporogonia ; selecting the immature ones, notice 

 under a low power 



a. The perianth ; its deeply notched margin, which 

 is usually twisted over the fruit ; observe the 

 cellular structure. Draw. 



b. Tear away the perianth, examine the surface of 

 the sporogonium and its stalk, and notice the 

 remains of the neck of the archegonium. 



c. Crush some of the sporogonia by pressing upon 

 the cover-glass, noticing the escaping contents 

 consisting of slender threads having granular 

 protoplasm and pointed ends, the immature elaters, 

 and rows of young spores, both radiating from the 

 base of the fruit. Draw. 



d. Examine some mature spores ; notice 

 i. The wall. 



ii. The contents. 



e. Examine the mature elaters ; notice 



i. The delicate wall, not easily distinguished. 



ii. The spiral bands* 



iii. Examine some dry elaters without a cover- 

 glass, and observe the movements when damp- 

 ened by the breath. 



7 These archegonia, unless taken from a very young head, are mostly 

 sterile, not having been fertilized, as shown by the shriveled neck, and 

 the absence of a well defined protoplasmic mass in the basal cavity. 



8 Their number can be ascertained by the method used for Spirogyra, 

 P. 36. 



