EVOLUTION OF PHANEROGAMS 179 



distant periods with a new primitive form of terrestrial 

 plant-life. 



It is true that it is difficult to do more than guess the 

 plant type which was derived from the single sporosac 

 primitive hydrozoon, though it may have been possibly 

 the Ferns with their little sporangia ; but we feel surer in 

 concluding that coniferous plants generally have been 

 derived from a hydrozoal type or types bearing sporosac- 

 gonoblastidia. 



The Angiosperms we hold to have appeared at a much 

 later date, because their marine primitive type was much 

 later in its evolution. Its distinguishing feature was the 

 attached medusiform gonophore, and this, it is suggested, 

 finds representation in the flower of the present-day Angio- 

 sperm. The medusoid-containing gonoblastidium would 

 logically be represented in the Angiosperm flower raceme. 



Pig. 53 is a rough outline diagram of our theory of plant 

 evolution. 



