94 COROLLA. 



la are so distinctly marked, that it is perfectly easy to distin- 

 guish them; the colour usually constitutes a very striking mark 

 of difference ; the calyx being ordinarily green, and the corolla 

 of a more lively hue, but the colour is not always a criterion. 

 In some cases the calyx is beautifully coloured. In the Fi SCHIA, 

 (Lady's ear-drop,) the calyx is of a bright scarlet; you would, 

 no doubt, at first think it to be the corolla ; but if you remove 

 the scarlet coat, you may see, wrapped around the eight stamens, 

 a purple covering ; on taking off each piece carefully, you will 

 find four petals,* as distinct as the petals of a rose ; you will 

 then see that the outer covering must be the calyx. 



Linnaeus, made the following distinction between the corolla 

 and the calyx ; viz. that the corolla has its petals alternate with 

 the stamens, and the calyx has its leafets arranged opposite to 

 them. This rule is not found to be invariable ; it has led some 

 botanists to call that the corolla, which others have named the 

 calyx. It seems as if nature had not placed any absolute limits 

 between these two organs. 



The corolla sometimes falls off soon after the flowering, as in 

 the poppy; it is then said to be caducous; sometimes it fades 

 and withers upon the stalk, as in the blue bell ; it is then said 

 to be marescent or withering. 



Each simple part, of which the corolla is composed, is called 

 a petal. A flower with petals is said to be petalous ; without 

 petals, it is called apetalous. The petals are definite when their 

 number is not more than twenty ; they are said to be indejinitf 

 when they exceed that number. 



If the corolla is formed of one single piece, or petal, it is 

 monopetalous ; if of more than one, it is polypetalous. You 

 may sometimes find a difficulty in determining whether a corolla 

 is in one piece or more ; for monopetalous flowers often have 

 deep divisions, extending almost to the base of the corolla ; but 

 they must be divided at the base, or be in separate pieces, in or- 

 der to be considered as polypetalous. It is a good rule to con- 

 sider the parts into which a corolla naturally falls, as so many 

 petals. 



Monopetalous corollas (see Fig. 50), consist of the tube, 

 throat and limb. The tube is the lower part, having more or 

 less the form of a tunnel. The throat is the entrance into the 

 tube ; it is either open, or closed by scales or hairs. The limb 

 is the upper border of the corolla. 



* Some Botanists call these nectaries, but this seems to be making an unne- 

 cessary confusion in terms ; for they have as much the appearance of petal*, 

 as those of a rose or pink. 



How distinguished from the calyx ? Rule of Linnaeus Duration Parts of 

 the corolla Monopetalous Polypetalous corollas, how divided ? Forms of 

 mouopetalous corollas. 



