248 CRYPTOGAMS 



211. MOSSES 



Object. To learn what is meant by alternation of 

 generations. 



Method. Prepare a shallow flowerpot by filling it with 

 soil to within an inch of the top. Dampen it and set it in a 

 saucer of water so as to prevent drying out. Crush several 

 moss capsules on a piece of paper to obtain the spores and 

 sow them by blowing them over the soil in the pot. Cover 

 it with a glass plate and set it away in a shady place. 



When the spores have begun to germinate, examine a 

 portion with the magnifier and later with a low power. 



1. The protonemata will show numerous branching fila- 

 ments. Look for buds, which will develop into leafy moss 

 plants. Look for rhizoids, which are delicate hairlike struc- 

 tures used as roots. With a higher power look for chloro- 

 plasts. Draw a protonema, showing all structures. 



2. Procure specimens of Funaria, Mnium, or Polytrichum 

 in spring for use fresh, and preserve some in formalin, for 

 later in the year. 



Remove a rosette from the tip of one plant and place on 

 a glass slip in a drop of water. With a pair of needles, tear 

 it apart and examine with a low power. 



Look for flask-shaped organs, which will usually be found 

 floating in the water. These are the archegonia. Look 

 for club-shaped structures in like manner. These are 

 antheridia. 



If a drop of weak caustic potash be allowed to flow under 

 the cover glass, the archegonia will become clearer and the 

 egg can be seen within. 



If fresh antheridia be crushed and examined with a high 



