174 COMPOUND OEGANS OF PLANTS. 



flower, that of a Crassula, showing the alternation of the parts 

 of each verticil, and also an equality in the number of pieces 

 of which each verticil is composed. All the verticils are 

 separate from each other, and the parts of each are equally 

 distinct. 



Assuming this complete and symmetrical flower to be the 

 normal plan or type on which flowers are constructed, when 

 we examine the various plants around us we find that most of 

 them are in an abnormal state, and we are able only to cite a 

 very small number whose flowers preserve this complete, 

 symmetrical, and regular condition. In the immense majority 

 of cases the regularity is destroyed, and the symmetry disguised 

 by a variety of causes. The following are those which act the 

 most frequently : — 



One or more additional verticils of the same organs have 

 been developed. — Thus in Ranunculus we have five sepals, five 

 petals, and numerous stamens and pistils ; this is occasioned 

 by the development of additional whorls of stamens and pistils. 

 A multiplication of stamens also occurs in other plants, as in 

 Anemone and Hypericum. 



The composition of the flower is somewhat difierent in 

 Dicotyledons and Monocotyledons. In the first, it is the num- 

 ber five or one of its multiples which commonly predominates. 

 Thus the calyx is generally composed of five sepals, the corolla 

 of five petals, the androeoium of five, ten, or twenty stamens, 

 and the gymnoecium of five pistils or some multiple of that 

 number, the parts of all the extra verticils alternating with 

 each other. Fig. 74 is a diagram of the flower of the Ranun- 

 culus with five sepals, five petals, and numerous stamens and 

 carpels in alternating rows of five each. This orderly distribu- 

 tion of a certain number of parts is called symmetry, and a 



