44 



ORaANOaUAPHY. 



they are together called the essential organs of the 

 flower. The calyx and corolla may or may not be present 

 without directly influencing the pro- 

 duction of seed. When present, they 

 surround the essential organs and pro- 

 tect them, hence they are called pro- 

 tecting organs. They are also called 

 the perianth (Gv.peri, around ; anthos, 

 flower). 



53. A flower with the four parts present is called a com- 

 plete flower; but if one or more of the parts are absent, 

 the flower is said to be incomplete. If the essential 

 organs are present it is called a perfect flOTver. Those 

 ■with stamens only (called staminate flowers), and those 

 \Yith pistils only (called pistillate flowers), are imperfect. 

 If the parts are alike among themselves, — that is, all the 

 sepals alike in shape and size, all the petals alike in shape and 

 size, and all the stamens alike in shape and size, — the flower 

 is said to be regular (Fig. 97). If this likeness in shape and 

 size does not obtain in any one set of organs, the flower is 

 said to be irregular (Fig. 98). If the petals, sepals, and sta- 

 mens are of the same number, or the latter twice or thrice that 

 number, the flower is said to be symmetrical ; but if the 

 number is not the same in 



each whorl, the flower is 

 unsymmetrical. 



54. If the relative in- 

 sertion of the floral parts 

 be examined, two types 

 will be found to prevail. In the one case each petal is 

 inserted directly in front of or within a sepal, and each 



Fig. 97. Kalniia blossom, a regular flower. Fig. 98. Flower of Lobelia, irregular. 



