174 



PRACTICAL BOTANY. 



rnr, . _. 



amine the pedicel with a magnifying glass and notice the 

 rhizoids and leaf scales along the grooves. Examine a 

 cross section of the pedicel under low power. Draw. 



Examine the same sec- 

 tion under high power, 

 noticing particularly the 

 rhizoids and leaf scales 

 as seen in section. 



With a magnifying 

 glass observe the anther- 

 idia on the upper sur- 

 face of the receptacle. 

 Imbed in pith and make 

 vertical sections through 

 the central part of the 

 receptacle. Under high 

 power find the anther- 

 idia in their somewhat 

 ovoidal cavities. Draw. 

 Near the antheridia one 

 celled, hairlike paraphy- 

 ses may be found in 

 specimens that are not 

 too mature. In the case 

 of mature antheridia, 

 antherozoidsmaybe seen 

 in the cells or swimming 

 in the water. This ob- 

 servation is difficult ; 

 the antherozoids may, 

 perhaps, be obtained by 

 placing a drop of water 

 on the top of an anther- 

 idium, the upper part 

 of which has been 



FIG. 101. The archegonium of Marchantia 

 polymorpha in different stages of its 

 growth. I-V show it before fertiliza- 

 tion. The antherozoids, which are pro- 

 duced in the antheridia, and which are 

 shown in Fig. 97, enter at x, pass up 

 through the long neck, and fertilize the 

 oosphere. A sporogonium results. This 

 is seen in different stages in VII and 

 VIII, which also show the shriveling of 

 the cells of the neck that occurs after 

 fertilization. IX shows a developing 

 sporogonium filled with spores and 

 elaters; a is the neck of the arche- 

 gonium wholly withered up. (After 

 Goebel.) 



