294 CALYX AND COROLLA. 



more interest, on account of the varied and beautiful forms and 

 colours they present ; namely, its external leafy portion. This 

 may be altogether termed the perianth^ or floral envelope ; the 

 essential portion of the flower being, as before explained, the 

 stamens and pistil that occupy its centre, which are sometimes 

 destitute of any protection. The perianth may be regarded as 

 consisting, in its most regular form, of two circles (arranged like 

 the whorls or verticils of leaves) of leafy organs ; of which the 

 outer circle is generally green, and the inner one coloured.* Of 

 this outer circle, the leaves or sepals not unfrequently grow 

 together, or adhere, at their edges; so that a sort of cup is 

 formed; hence the whole is termed the calyx (cup). The inner 

 whorl is termed the corolla, and its divisions are called petals; 

 they not unfrequently grow together in the same manner (as in 

 the Campanula or Harebell) forming a second cup within the 

 calyx. 



456. When the Calyx seems formed of but one piece, in con- 

 sequence of the adhesion of its leafy portions, it is said to be 

 monosepalous (possessing but a single sepal) ; and when the petals 

 have united in a similar manner, the corolla is said to be mono- 

 peialous.\ Though these terms are not strictly correct (since 

 there are really as many sepals and petals in the one case as in 

 the other), they are convenient, and are often employed in 

 describing plants. The terms yamosepalous and gamopetalous 

 have been introduced to designate these forms of calyx and 

 corolla ; their signification being, that the sepals and petals are 

 united or married at their edges. The real nature of such a calyx 

 or corolla is shown by varieties, or monstrosities, like that deli- 

 neated in the adjoining figure; here the regular form of a 



* In Botanical language, the term coloured always means, that the part is not 

 green ; green being regarded as no colour in Plants. A white flower is spoken of 

 as coloured. 



f It is worthy of inquiry, whether it would not be more proper to consider the 

 monosepalous calyx and the mouopetalous corolla (and even many of those in 

 which the sepals and petals are distinct), as consisting of so many leaflets^ or parts 

 of a single leaf; in the some manner as, according to a suggestion formerly made 

 (. 303, note), some verticils probably consist not of a number of leaves, but of 

 a single one, divided into leaflets. 



