CELLULARES, OK CELLULAR PLANTS. 

 Fig. 29. 



71 



u. Bryum cuspidatiun in fruit, natural size. 6. The cuoulliform calyptra detached 

 from the sporangium, c. Magnified sporangium, from which the operculum or lid 

 (d) has been removed to show the peristome or mouth of the sporangium, k. A por- 

 tion of the inner and outer peristome highly magnified. /. Physcomitrium pyriforme 

 in fruit, showing the mitriform calyptra. g. The calyptra detached from the spo- 

 rangium (h). i. The operculum or lid removed from the sporangium, showing it to 

 be destitute of a peristome. 



The outer peristome usually exhibits a number of broad, 

 short, lanceolate processes called teeth, and the inner is 

 developed into long filamentous cilia (cUium, an eyelash). 

 Sometimes there is only one peristome or fringe, or the 

 membrane, instead of being developed into teeth or ciliae, 

 may stretch across the mouth of the sporangium and close 

 it altogether, as in the genus Atriohium; or, perhaps, 

 neither of the membranes is developed, and the sporangium 

 is without a peristome, as in the genus Physcomitrium. 



