The Angiosperms 161 



ledons and dicotyledons occur in the Infra- 

 Cretaceous rocks ; but the evidence of the occurrence 

 of either group in earlier formations is extremely 

 doubtful. If we try to determine the question from 

 a study of the living forms, the matter is equally 

 difficult. Among both monocotyledons and dicoty- 

 ledons, flowers of equal simplicity are met with. 

 Such monocotyledons as the arums, pond-weeds, 

 or screw-pines may be compared to such apetalous 

 dicotyledons as the peppers or willows; while the 

 primitive type of amphisporangiate flowers with its 

 indefinitely multiplied free parts, like the magnolia 

 and buttercup, occurs also in the water-plantain 

 and some other low monocotyledons. 



There is no doubt that as a whole the monocoty- 

 ledons are simpler than the dicotyledons, but the 

 question then arises, whether this greater sim- 

 plicity is not in many cases secondary, the 

 result of reduction. The same difficulty is again 

 met with in comparing the embryo, whose char- 

 acter gives name to the two series. While most 

 dicotyledons, as their name implies, have embryos 

 with two cotyledons, there are some in which 

 but one is present, and the question whether 

 the monocotyledonous or dicotyledonous condition 

 is more ancient still remains open. It is quite con- 

 ceivable that the two divisions, as usually recognized, 

 do not necessarily represent two closed develop- 

 mental series, and whether we consider monocoty- 

 ledon or dicotyledon as the more primitive type, 



