CH. Xl] BUTTERCUP. 143 



point is a leaf-like character; so is their arrangement in 

 spirals or in circles (whorls) on the axis. Deformed or 

 monstrous flowers supply interesting evidence : almost any 

 part of the flower may abnormally take on an obviously 

 leaf-like form. And in some cases the axis which bears 

 petals below is prolonged beyond the flower and bears 

 ordinary green leaves. 



A FIG. 63. B 



A. KANUNCULUS FLOWER FROM WHICH THE SEPALS, PETALS, AND ALL BUT 



TWO STAMENS HAVE BEEN REMOVED. 



B. KANUNCULUS FLOWER DIVIDED LONGITUDINALLY. 



(From Le Maout and Decaisne.) 



The floral leaves are divided into two main groups. 

 (1) Those which are essentially reproductive; and (2) 

 those which are not essential to reproduction. Fig. 63 A 

 shows a buttercup stripped of the non-essential parts and 

 retaining part of the reproductive leaves grouped round 

 the central axis. Fig. 63 B shows a longitudinally divided 

 flower in which the non-essential parts of the flower are 

 also shown. They consist of ten flattened leaf-like organs 

 arranged in two groups of five each. In the horse- 

 chestnut we had an instance of leaves springing from 

 the stem opposite one another at the same level. In 



