VARIATIONS IN STRUCTURE 



279 



in the other all with fewer than ten stamens. This, as you 

 can see, was a convenient classification, but not a natural 

 one. It was an 

 artificial classifi- 

 cation ; it was 

 like classifying 

 horses by the 

 white spots on 

 them ; it did not 

 indicate true kin- 

 ships. True kin- 

 ships are based on 

 descent from the 

 same ancestors. 



Gradually bot- 

 anists have 

 discovered the 

 principal relation- 

 ships of flower- 

 ing plants. We 

 know that similar 

 flowers indicate 

 similar ancestors, 

 but we no longer 

 classify simply on 

 the basis of the 

 number of sta- 

 mens. The char- 

 acteristics of the 

 flowers and of 

 other organs as 

 well are consid- 



FiG. 100 A. — Jack-in-the-pulpit {Arisama triphyllum) . 

 A , top of the plant showing spathe with spadix pro- 

 truding from it. S, The corm, which is called 

 Indian turnip. (See page 160.) 



This plant is usually dicecious (see page 284) and the 

 flowers are very simple. C shows a spadix bearing 

 pistillate flowers, the spathe having been removed. D, 

 a spadix bearing staminate flowers. E, the fruit, which 

 turns scarlet ; note the withered remnant of the club- 

 shaped part of the spadix. 



