THE EVIDENCE 95 



find in Magnoliaceae or their near allies. This 

 character has suggested to Dr. Wieland that the 

 Mesozoic Cycadophytes may also have had 

 an affinity with Dicotyledonous families much 

 higher up in the scale, the Convolvulus family, 

 for example. On this view a number of lines 

 of evolution would have started in various 

 directions from ancestors allied to the Bennet- 

 titese. At present all this is very speculative; 

 at any rate, it is clear that the flowers of the 

 Mesozoic Cycadophytes were highly organised 

 structures; if it was from ancestors such as 

 these that the higher Flowering Plants were 

 descended, the evolution of the flower must 

 have been often a process of reduction to greater 

 simplicity, and the simplest flowers of Angio- 

 sperms would seem to be the furthest from the 

 primitive type. 



If, as seems to be now the most likely view, 

 the Dicotyledons sprang from the great class 

 of Cycadophytes which overspread the world 

 in Mesozoic times, the question remains, what 

 was the origin of the Monocotyledons? There 

 is nothing to connect them directly with the 

 Cycadophyta or any other Gymnosperms, and 

 we can only suppose that they branched off from 

 the Dicotyledons soon after the latter started 

 as a line of their own. Much ingenious work 

 has been done on this question, and it has been 



