THE MOSS 



129 



1. The antheridia, elliptical, cellular structures with short 

 stalks. The upper part is a sperm case and opens at the 

 end by the swelling and rupture of a special group of cells. 

 Draw a mature antheridium and then crush, if possible, 

 to study its contents of developing sperms. Stain the 

 crushed preparation with iodine, which may show some 

 details of the structure of the sperms. 



2. Cxreen filaments, paraphyses, among the antheridia and 

 rising above them. Observe the form and contents of the 

 cells and draw. 



Make a semidiagrammatic sketch of how a lengthwise sec- 

 tion of the tip of an antheridial plant would appear, using 

 prepared slides when possible, as described in 3. 



3. Lengthwise microtome sections of the tips of antheridial plants 

 (Sec. 212) present stages in the development of the antheridia 

 and details of their cell structure and the development of the 

 sperms. 



F. The archegonia, or female sexual organs. Tease apart the 

 enveloping leaves around the end of an archegonial plant 

 Note : 



1. The stalked archegonia with very long necks. Older 

 stages will show the necks open above and the eggs in the 

 swollen bases. Younger stages will show unopened necks 

 with the row of canal cells. Draw. 



2. Delicate filaments, paraphyses, among the archegonia. 



^ Make a semidiagrammatic sketch of how a lengthwise sec- 

 tion of the tip of an archegonial plant would appear, using 

 prepared slides if possible, as described in 3. 



3. Lengthwise microtome sections of the tips of archegonial plants 

 (Sec. 212) present details of the structure and development of the 

 archegonia and frequently of the young sporophytes. 



G. The development of the sporophyte. Study material in 

 which developing sporophytes are still contained within 

 the enlarged sac-like archegonium, now called the calyptra. 

 Split the calyptra with a point of a needle and remove it from 

 the needle-shaped sporophyte. Pick the young sporophyte 



