THE COROLLA 43 



different forms of corolla, under which examples illustrating each will be 

 given. 



The calyx usually remains after the corolla and stamens have fallen, 

 sometimes even until the fruit matures — in either case it is said to be 

 persistent. If it falls with the corolla and stamens, it is deciduous, and 

 if when the flower opens, caducous, as in the Poppy and May-apple. It 

 is often more or less adherent to the ovary or base of the pistil, and it is 

 important, in plant analysis, to note the presence or absence of such 

 adhesion, which is indicated in a description by the terms inferior, or 

 non-adherent (hypogynous) , when free from the ovary and wholly be- 

 neath it; half -superior, or half-adherent (perigynous), when it partially 

 envelops the ovary, as in the Cherry; superior or adherent (epigynous), 

 when it completely envelops it, as in the Colocynth. 



The Corolla. — The Corolla is the inner floral envelope, usually 

 delicate in texture, and showing more or less brilliant colors and combi- 

 nations of color. Its parts are called Petals, and when the calyx closely 

 resembles the corolla in structure and coloring they are together called 

 the Perianth. The purpose of these envelopes is to protect the repro- 

 ductive organs within, and also to aid in the fertilization of the flower, 

 as their bright colors, fragrance and saccharine secretions serve to 

 attract pollen-carrying insects. 



Forms or the Corolla and Perianth. — When the petals are not 

 united with each other, the corolla is said to be Choripetalous, often 

 called Polypetalous. When more or less united, they are Gamopeta- 

 Lous, often called Sympetalous. 



When the distinct petals are four in number, and arranged in the 

 form of a cross, the corolla is called Cruciform. Ex. : Mustard and 

 other plants belonging to the order Cruciferee. 



The Papilionaceous corolla is so called because of a fancied re- 

 semblance to a butterfly. The irregularity in this form is very striking, 

 and the petals bear special names: the largest one is the vexillum, or 

 standard; the two beneath it the alse, or wings; the two anterior, the 

 carina or keel. Ex. : Locust, Pea, and Clover. 



Orchidaceous flowers are of peculiar irregularity, combining calyx 

 and corolla. The petal in front of stamen and stigma, which differs from 

 the others in form and secretes nectar, is called the Labellum. Ex.: 

 Cypripedium and other Orchids. 



When calyx and corolla each consist of three parts closely resem- 



