THE GREAT GKOUPS OF PTEKIDOPIIYTES 



165 



The solitary sporangium appears in the axils (upper 

 angles formed by the leaves with the stem) of the leaves 

 and sporophylls, but arise from the stem instead of the 



Fig. 139. Selaginella Martensii: A, branch bearing etrobili; B, a microsporophyll 

 with a microsporancium, showing microspores through a rupture in the wall; C, 

 a megasporophyll with a megasporangium ; D, megaspores : E, microspores.— 



GOLUBEUGEU. 



29 



