THE EVOLUTION OF THE FLOWER 119 



decrease in the size of the foliage as we approach 

 the flower head. Finally the green processes lose 

 their distinctive form altogether, until just below 

 the flower they drift into simple lobes, which bear 

 a striking resemblance to the bracts that encircle 

 the flower. 



We can thus trace a definite connection between 

 the sepals of the flower and the foliage of the plant. 

 Going beyond this, it is not a difficult matter to 

 find a distinct relationship existing between the 

 calyx and the corolla. The Tulip is an excellent 

 case in point, for except that the sepals are, of 

 course, on the outside of the petals, there is really 

 nothing to distinguish them. Now, if we observe 

 a large number of cultivated blossoms we shall 

 certainly find that in not a few cases the sepals 

 are partly or wholly green, proving beyond a 

 shadow of a doubt whence they have their origin. 

 Perhaps a still more striking proof of the leaf 

 origin of both sepals and petals is to be 

 seen in the flower of the Snowflake (Leucojum 

 cestivum). Each portion of the perianth is tipped 

 with a dot of pure green, and this spot stands 

 up in vivid contrast to the snowy whiteness of 

 the organ. For what special purpose this con- 

 spicuous marking of green may have been retained 

 it is not easy to say ; it is all-sufficient to indicate 



