MULTIPLICATION IN PLANTS 479 



Fertilization within ovule 



Development of zygote within ovule 



Supply of food for developing embryo from ovary parent 



Supply of protective structures by ovary parent 



6. Fruit in relation to reproduction 



Origin 



Ripened ovary + various adhering parts (calyx ; receptacle ; 

 involucre) 

 Relation to seed 

 Protection 

 Spines 

 Hard shell 



Taste disagreeable to animals 

 Escape and distribution 

 Dehiscence 

 Pores 



Rot away or are eaten 

 Breeze-catchers 

 Wings ; fluff etc. 



7. Seed distribution 



Factors related to preservation of species 



Numbers 



Wide dispersal 



Finding of favorable lodgment 

 Means of distribution 



By action of fruit 



By moving animals 



By wind 



By water 



QUESTIONS 



1. What do you consider the lowest form of reproduction in plants ? 

 Why ? W^hat do you consider the highest form ? Why ? 



2. What results from cell division in plants besides the formation of 

 new individuals ? 



3. How does cell division as a means of reproduction differ from 

 spore formation? 



4. In what ways are a spore and a zygote alike? In what ways are 

 they different? 



5. How do the gametes of Spirogyra resemble the gametes of rock- 

 weed ? In what ways are they different ? 



