PTERIDOPHYTES 



149 



Among the Bryophytes the sporogenous tissue appears 

 very early in the development of the sporogonium, the pro- 

 duction of spores being its only function ; also there is a 



Fro. 129. A moonwort (Botrychi- 

 um), showing the leaf differen- 

 tiated into foliage and sporophyll 

 branches. After STRASBURGER. 



FIG. 130. The adder's tongue (Ophioglossum 

 vulgatum), showing two leaves, each 

 with a foliage branch and a much longer 

 sporophyll branch. After MARION SAT- 



TBRLEE. 



