ACTION OP FLOWEES. 55 



CHAPTER V. 



ACTION OP FLOWERS. 



Structure of Flowers. — Names of their Parts. — Ten- 

 dency of the Parts to alter and change into each other, 

 and into Leaves. — Double Flowers. — Analogy of 

 Flowers to Branches. — Cause of the Production of 

 Flowers. — Of Productiveness. — Of Sterility. — Uses of 

 the Parts of a Flower. — Fertilization. — Hybrids. — 

 Oros^eed^s. 



79. A Flower is that part of a plant wMcli is 

 formed for the purpose of reproducing the species 

 by means of seeds. It consists of floral envelopes 

 and sexes. 



80. The floral envelopes are : 1. the calyx, which 

 is usually green, and always the most external ; and, 

 2. the corolla, which is commonly thin, gaily coloured, 

 more fugitive than the calyx, and placed next within 

 it ; each of these consists of leaves, called sepals in the 

 calyx, and petals in the corolla. Both calyx and 

 corolla are usually present ; but in some cases only 

 one envelope is formed, as in the Marvel of Peru ; and 

 in other cases the flower has no envelopes, as in the 

 Willow. Envelopes are, therefore, not a necessary 

 part of a flower. 



81. In the middle of the flower stand the sexes, 



