308 



LYCOPODIALES 



FIG. 155. 



Isoetes lacustris, L. A= plant of natural size. B = base of a fertile leaf with 

 ligule (/), and sporangium (sp) seen from above. C = longitudinal and D transverse 

 sections of the leaf-base; sp = sporangium ; /=ligule. (From Rabenhorst's, Krypt. 

 Flora.') 



