Seed Plants : Gymnosperms 301 



(2) The development of a conductive system which made 

 possible the growth of aerial parts situated at a distance 

 from the water supply, and which also made possible the 

 transportation of food to roots that live in the dark and there- 

 fore are not able to make their own food. 



(3) The development of seeds as a means of dispersing the 

 plant and of preserving it during seasons unfavorable for 

 vegetative hfe. 



(4) The development of an extensive root system by which 

 larger amounts of water and mineral salts are made acces- 

 sible. Correlated with this is the development of large, 

 much-branched tree forms. 



(s) The development of true flowers made up of floral leaves, 

 stamens, and pistils. With this step came insect poUination 

 and the production of seeds inclosed in an ovulary. In some 

 cases the ovulary is fleshy and at maturity becomes an edible 

 fniit. 



