A MANUAL OF BOTANY 137 



and then place in water. What liai)pons ? Did tlic changes 

 caused by soaking occur slowly or rapidly ? Did it dry 

 rapidly? Apply this, if you can, to the explanation of 

 why mosses are not killed by great drought or Arctic cold. 

 Wliat benetit to the moss is the crowded habit of living? 

 What would you infer to be the food of mosses ? Of what 

 use to man are mosses ? Read about peat and fuels pre- 

 ]);u-ed from this substance. If possible, examine si)ecimens 

 of spJuif/nnm, a bog moss, and observe how it differs from 

 the common mosses. The two groups are subgroups of the 

 moss class. Find out what you can about sphagnum and 

 sphagnum bogs. 



How may mosses be related to alga?? What similar 

 features do they have ? 



What are so-called moss flowers ? Why do you not find 

 mosses ordinarily with sporophytes attached ? 



Drawings. Make careful drawings as follows : — 



1. Several mosses (m) to show variation in form and 

 size. 



2. A complete moss (note size) and (m) 



3. Leaves of different species (m). 



4. Leaf (Ij^) to show cell structure. 



5. Leaf section (Ij)). 



G. Leaf cell chloroplasts {!/)). 



7. Rhizoids (//>). 



8. Capsule (/y>) with idl the parts. 



9. Prepared antheridia and archegonia. 



SECTION TV. TIIF FKRX PLANTS 



Class 1. r'i:iiNs Pijoi'ER 



General statement. Ferns may be obtained fresh from any 

 greenhouse at any time of the year and in sufficient quantities 

 to study the leaves and their vegetative features. For much 

 of the work, dried and carefully mounted material is prefer- 



