LIFE HISTORY OF FERN 



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attached to prothallus with well-developed first leaf and root ; 

 st., stem (still small). G, pinnule of fern leaf from below showing 

 seven sori (so.) and ripe sporangia (spg.) protruding from below 

 membrane of sorus. H, single sporangium opening to set free 

 spores (sp.). I, spore (sp.) germinated to form prothallus ; rh., 

 rhizoids; a, apical cell. 



