THE VEGETABLE KINGDOM. 



389 



Most frequently the perianth is double. Its external 

 envelope, or calyx, is formed by the first whorl of meta- 

 morphosed leaves, and as the transformation of these is 

 much less radical than in the other parts, the different 

 parts of this organ, or the sepals, in many cases remind 

 us of the leaves by their structure and colouring. The 

 internal envelope, or corolla, although more brilliant than 

 the other, is nevertheless also formed by a whorl of leaves 



211. Petaloid Perianth of the White Lilj—Lihum candidum (Linnreus). 



—the second. Each of these leaves is called a petal. The 

 stamens, which represent the male apparatus of plants, 

 result from the metamorphosis of the third whorl of 

 leaves; these depart so far from their normal type that 

 analogy alone shows what their fundamental structure 

 really is. Finally, the pistils, real organs of maternity, are 

 derived from the fourth, or most internal foliaceous ring. 

 Simple analogy made the naturalists of antiquity sup- 



