THE GREAT GROUPS OF BRYOPHYTES 



125 



light containing chlorophyll, and those in the substratum 

 being colorless and acting as rhizoids. The leafy gameto- 

 phores are often highly organized (Figs. 102, 106), the 

 leaves and stems showing a certain amount of differentia- 

 tion of tissues. 



It is the sporophyte, however, which shows the great- 

 est amount of specialization (Fig. 107). The sporogonium 



Fig. 107. A common moss (F>inariai: in the center is the leafy shoot (gametophore\ 

 with rhizoids. several leaves, and a sporogonium (sporophyte), with a long seta. 

 capsule, and at its tip the calyptra (calr, to the right a capsule with calyptra re- 

 moved, showing the operculum (o>; to the left a young sporogonium pushing up 

 the calyptra from the leafy shoot.— After Campbell. 



has a foot and a long slender seta, but the capsule is espe- 

 cially complex. The archesporium is reduced to a small 

 hollow cylinder (Fig. 88), the capsule wall is most elabo- 

 rately constructed, and the columella runs through the 



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