INTRODUCTION TO CRYPTOGAMIC BOTANY. 



557 



as to the details of the spicate fruit, departs greatly in habit, 

 being, as to other points, almost a precise repetition of the 

 Ophioglossoid Rhisoglossum ; while Isoetes connects these 

 plants evidently with Marsileacece. 



Fig. 124. 



a. Spore of Selaginella helvetica, shortly after it has been sowed, 

 divided vertically. 



b. Archegonium of Selaginella denticulata, after impregnation. 



c. Young embryo of ditto. 



d. PTothallus of ditto, with archegonia, one of which has produced 

 an embryo. 



^ m 



Fiff. 125. 



Fio;. 12G. 



Mouth of archegonium of Se- 

 laginella denticulata, seen from 

 above and laterally. 



Embryo of Selaginella Mar- 

 tensi. 



These three figures, which are all more or less magnified, are 

 from Hofmeister. 



