MARCHANTIA POLYMORPHA. 65 



at an acute angle next the pedicel, and by an 



infolded flap next the edge of the receptacle. 



This flap is best seen by spreading apart the 



rays between which the perichaetium is 



situated, 

 iv. Remove the perichaetium and spread out on 



the slide with the sporogonia already placed 



there ; notice 



a. The fimbriated free edge of fatperichatium. 



/3. The opaque sporogonia with their very short 

 thick stalks, each inclosed by a delicate 

 sheath, the perianth, twice the length of 

 the immature sporogonia, but equaling 

 or even shorter than the older ones. 

 Draw. 



v. Tear away the perianth and notice that it is 

 quite free from the sporogonium, which, with 

 its stalk, can now be seen more clearly. Draw. 



d. In a head from a fresh specimen 4 having mature 

 sporogonia protruding from the perichaetia, notice 



i. The /<?;/ of the sporogonia. 



ii. The contents ; a fluffy yellow mass when 



escaping from a freshly ruptured fruit, 

 iii. Mount and notice the dust-like part, spores, 



and the short delicate hairs, elaters. 

 iv. Breathe gently upon a mass of dry elaters and 



notice the movement caused by the moisture 



of the breath. 



e. Draw an uninjured archegonial branch, giving 



prominence to the under surface of the head. 



4 An alcoholic specimen does as well, except to illustrate ii and iv 

 infra. 



