The Angiosperms 163 



such as occurs in the screw-pines and willows, and 

 the amphisporangiate type of the magnolia and 

 water-plantain, may be equally primitive, and not 

 derived one from the other. 



Whether these two types first arose in mono- 

 cotyledons or dicotyledons must remain for the 

 present an open question. It is quite likely that 

 the primitive angiosperms were not clearly divided 

 into monocotyledons and dicotyledons as they are 

 now understood. From this primitive stock pre- 

 sumably more than two series arose, and these may 

 have started with either type of flower. Thus at 

 present some of the so-called Ranales, i.e., butter- 

 cups, water-lilies, etc., are dicotyledonous forms 

 which are almost certainly directly related to such 

 monocotyledonous types as the water-plantain and 

 pond-weeds; while we believe a similar relationship 

 exists between the monocotyledonous arums and the 

 dicotyledonous peppers. Thus, while it is reason- 

 ably certain that all of the angiosperms belong to 

 a common stock, it by no means follows that there 

 may not have been developed from this more than 

 one line both of monocotyledons and dicotyledons. 



MONOCOTYLEDONS 



Whether or not the monocotyledons are more 

 primitive than the dicotyledons, there is no question 

 that as a class they are decidedly simpler, both in 

 their external form and in their tissues. As their 



