146 THE EVOLUTION OF PLANTS 



The sporangia, as already mentioned, were 

 often much like those of the Osmundas, having 

 a patch of thickened and enlarged cells on one 

 side. In other cases greater elaboration was at- 



g 



g 



g 



LAB.<* 



Fig. 15. Stauropteris. Sporangium containing numerous 

 spores, some of which, at the places lettered, are germinating. 

 X about 70. 



tained; the sporangia were of large size and the 

 apparatus for discharging the spores was on a 

 corresponding scale. Sometimes there was an 

 approach to the ring-mechanism of most modern 

 Ferns, but the ring was usually, if not always, 

 more than one cell in width. In other species 



