LICHENS. 95 



Preservation. The Lichens are readily preserved, 

 on account of their dry nature ; they need simply be 

 kept in a dry place, and glued to pieces of card. If 

 room is an object, they may be dried under pressure, 

 as in the case of the flowering plants. When re- 

 moistened, the minute structures may be easily made 

 out by sections. The smaller ones may be mounted 

 dry, in cells made of the wax cement (p. 16). The 

 minute structures keep well in chloride of calcium or 

 glycerine. 



