ORGANS OF REPEODUCTION. 



41 



white, yellow, or red, which by their position to each 

 other have the appearance of a large open flower. In 

 many plants the calyx generally falls away soon after the 

 opening of the flower ; or is more permanent, increasing 

 in size, and becoming inflated, as the winter cherry, or it 

 becomes fleshy like an apple, which is only the tube of 

 the calyx enlarged, and embedding the ovary. In the 

 lily and allied families the calyx is not obviously distinct 

 from the corolla, the flowers consisting of six parts, 

 generally of uniform size and colour; it is however^ 

 found that they are in two whorls of three each, the three 

 lower representing the calyx; in some the parts are 

 more or less united, forming a monopetalous flower ; the 

 term perianth is usually applied to cases of this kind. 



In the genus Eucalyptus (gum trees) and the yellow- 

 flowered plant known as Eschscholtzia, the calyx, instead 

 of opening in the usual way, becomes transversely cir- 

 cumcised, the upper portion falling away in the form of 

 a cap or extinguisher, the margin of the lower part re- 

 presenting a ring. This kind of calyx is called oper- 

 culum. 



Corolla. — The corolla is always seated within or on 

 the calyx. It consists of one, two, or many pieces called 

 petals ; when in one piece it is monopetalous, when of 

 two or more pieces, polypetalous. Monopetalous co- 

 rollas, when spreading and nearly flat, are called salver- 

 shaped, as in the primrose (fig. 2, a) ; funnel-shaped, 

 as in the convolvulus, rhododendron, azalea, and gardenia; 

 campanulate, or bull-shaped, as Canterbury bell and gen- 

 tianella; ringent (gaping), as in monkey flower ; labiate, 

 or lipped, as in sage, thyme, foxglove (fig. 2, h) ; tubular, 

 long and of equal width like a tube, as in the trumpet 

 honeysuckle ; urceolate, swelling out in the middle, and 



