MOSSES. 



161 



are ripe, if we make a section through a cluster, or if we merely tease out 

 some from the end with a needle in a drop of water on the slide, then prepare 

 for examination with the microscope, we will see the form of the antheridia. 

 They are somewhat clavate or elliptical in outline, as seen in fig. 201. Be- 

 tween them there stand short threads composed of several cells containing 

 chlorophyll grains. These are sterile threads (paraphyses). 



338. Sporogonium. — In fig. 197 we see illustrated a sporogonium of mnium, 

 which is of course developed from the fertilized egg cell of the archegonium. 

 There is a nearly cylindrical capsule, bent downward, and supported on a long 



Fig. 201. 



f ig. 200. Antheridium of mnium 



Section through end of stem of female plant of mnium, show- with jointed, paraphysis 

 ing archegonia at the center. One archegonium shows the egg. at _ the left ; spermato- 

 On the sides are sections of the protecting leaves. zoids at the right. 



slender stalk. Upon the capsule is a peculiar cap,* shaped like a ladle or 

 spatula. This is the remnant of the old archegonium, which, for a time sur- 

 rounded and protected the young embryo of the sporogonium, just as takes 

 place in the liverworts. In most of the mosses this old remnant of the arche- 

 gonium is borne aloft on the capsule as a cap, while in the liverworts it is 

 thrown to one side as the sporogonium elongates. 

 339. Structure of the moss capsule. — At the free end on the moss capsule 



* Called the calyptra. 



