14 



INTEODirCTIOK. 



§ 9. Tlie Calyx and Corolla or FeriantJi. 



Tlie Calyx is usually green, and smaller than the corolla ; sometinies very- 

 minute, rudimeutai'y, or entirely wanting ; sometimes very indistinctly 

 tvhorled, or not whorled at all, or composed of a large number of sepals of 

 which the outer ones pass gradually into bracts, and the inner ones into 

 petals. 



The Corolla is usually coloured, and of a more deHcate texture than the 

 calyx, and, in popular language, is often more specially meant by th.eJJoioer 

 Its petals are more rarely indefinite in number, and the whorl more rarely 

 broken than in the case of the calyx, at least when the plant is in a natiu-al 

 healthy state. What are commonly called double floioers are in most cases 

 a kind of monster or deformity, of accidental origin, though more or less 

 permanent in cultivation, in which the ordinary number of petals is mul- 

 tiplied by the conversion of stamens, sepals, or even pistils into petals, by 

 the division of the ordinary petals, or simply by the addition of supernu- 

 merary ones. Petals are also sometimes very small, rudimeutaiy, or entirely 

 deficient. 



In most cases however the so-caUed simple perianiJt is one in which the 

 sepals and petals are similar in fonn and texture, and present apparently 

 a single whorl. Strictly speaking it will be generally fomid that one 

 half of the parts (called leaves or segments) of the simple perianth are in 

 fact outside the others, at least in the young bud, and that there is some 

 slight difference .in their texture, size, shape, or colour, indicating to the 

 close observer the presence of both calyx and corolla : hence much discre- 

 pancy in descriptive works. Where one botanist describes a simple peri- 

 anth of six segments, another will speak of a double perianth of three se- 

 pals andJ^hree petals. 



In the following terms, the prefixes expressive of the modifications of 

 fonn of the corolla and its petals are equally applicable to the calyx and its 

 sepals, and to the simple perianth and its segments. 



The Corolla is said to be monopetalous when the petals are united either 

 entu'ely, or at the base only, into a cup, tube, or ring ; poli/petalons when 

 they are all free from the base. These expressions, established by long 

 usage, are not strictly con-ect, for monopetalovs (consisting of a single pe- 

 tal) should apply rather to a corolla really reduced to a single petal, which 

 would then be on one side of the axis; and polypetalous is sometimes used 

 more appropriately for a corolla with an indefinite number of petals. Some 

 modern botanists have therefore proposed the term gamopetalous for the 

 corolla with united petals, and dialipetalous for that witli free petals'; but 

 the old-established expressions are still the most generally used. 



When the petals are partially united, the lower entire portion of the co- 

 rolla is called the tvhe; whatever be its shape, and the fi-ee portions of the 

 petals are called the teeth, lobes, or seriments, according as they are short or 

 long in proportion to the whole length of the corolla, ^^'iien the tube is 

 excessively short, the petals appear at first sight free, but their slight union 

 at the base must be carefully attended to, being of importance in classifica- 

 tion. 



The .Sastivation of a corolla is the arrangement of the petals, or of such 

 portion of them as is free, in tlie unexpandetl bud. It is 



va/rate, when they are strictly wliorled in their whole length, their edges 

 being placed against each other without overlajjping. 



imbricate, when the whorl is more or less broken by some of the petals 



