Bold • Development of Plants in Time 



289 



QUESTIONS 



1. With what degree of certainty may we 

 regard phylogenetic schemes of classi- 

 fication in contrast to evolution under 

 experimental conditions? 



2. What significance can be attached to 

 the fact that similar structures and 

 functions are found in diverse groups 

 of plants? 



3. What are some of the oldest known 

 organisms? 



4. Discuss the possible connection be- 

 tween ( 1 ) xylem and phloem, and ( 2 ) 

 the development of the terrestrial 

 habit. 



5. What are angiosperms and when do 

 they first make their appearance in the 

 rock strata? 



