404 



GENERAL MORPHOLOGY OF PLANTS 



552. Formula for life history of Gymnosperms.* This 

 could be written as follows, beginning with the sporophyte or 

 second generation. 



xMicrospore Male Gametophyte spernu 



^ (pollen grain) (pollen grain lube and contents') ^ 



N Macrospore Female Gametophyte egg / 



(beginning of (endosperm with archegonia) 



endosperm) 



Fertilized egg Sporophyte, etc. = 



/misp-MG-sx 



\ ma sp FG e / 



If the formula starts with the beginning of one of the alternating 

 stages and represents the beginning and end of each generation it 

 would stand thus, MC = mother cell of spores. 



2nd Generation isl Generation 



FE S MC 



mi sp MG s 

 ma sp FG e 



FE, etc. 



Endosperm and 

 Pollen Grain 



Diagram No. VI. Illustrating life cycle of a gymnosperm. Course of development 

 follows the direction indicated by the arrows. Zygote equals fertilized egg. Vegetative 

 multiplication by off shoots. Note the increase of the sporophyte and decrease of the game- 

 tophyte. 



* For reference. 



