FEEN 333 



manner study young sori. Examine some of the 

 mature sporangia in a drop of water. Notice 

 that each consists of a stalk, which bears the 

 capsule, within which are the spores. "What 

 is the structure of the stalk ? Of how many 

 rows of cells does it consist ? What is the struct- 

 ure of their walls? What do they contain? 

 What is the shape of the capsule ? l^ote the 

 marginal cells forming the annulus. What is 

 their shape ? Color ? Notice particularly their 

 arrangement and the structure of their walls. 

 Look for sporangia which have broken open 

 along the line of dehiscence. Where is this 

 line? If no such sporangia are found, crush 

 some by pressing on the cover-glass, or run a 

 drop of glycerine under fhe cover-glass. Draw 

 closed and open sporangia. 



How many spores does a sporangium contain ? 

 How are they arranged? Examine a single 

 spore and note its shape, size, color, structure, 

 contents, etc. Draw several spores. Examine 

 sections made through pinnules bearing ma- 

 ture and those bearing young sporangia. En- 

 deavor to make out how the sporangia are at- 

 tached in the sorus, how they develop, and how 

 the spores are formed within the capsule. Are 

 all the sporangia in one sorus of the same age? 

 Can you trace any structural relationship be- 

 tween the sporangia and the trichomes ? Note 

 also the structure of the indusium. 

 Make drawings of each structure examined. 



B. — The Proihallium or Sexual Generation. 



Procure prothallia from the greenhouse, or 



