MORPHOLOGY OF EEPEODUCTIVE ORGANS 157 



persistent, and forms a part of the fruit, as in the Quince (fig. 

 299), Apple, Pear, Melon, and Cucumber. When it is per- 

 sistent and assumes a shrivelled or withered appearance, as 

 in the species of Campanula, it is marcescent ; when it is per- 

 sistent, and continues to grow after the flowering, so as to 

 form a bladdery expansion round the fruit, as in the Winter 

 Cherry, and other species of Physalis (fig. 298), it is termed 

 accrescent. 



b. The Corolla. 



The coroUa is the inner envelope of the flower. It consists 

 usually of a single whorl of leaves, called petals. In a com- 

 plete flower (fig. 245,^;), it is situated between the calyx and 

 andrcecium, and is generally to be distinguished from the 

 former, as we have already seen, by its coloured nature and 

 more delicate structure. When there is but one whorl of perianth 

 leaves, as we have also before noticed, this is to be considered 

 as the calyx, and the flower is then termed apetalous or 

 monochlaynydeous. The corolla is usually the most showy and 

 conspicuous part of the flower ; in some rare cases, however, it is 

 green like the calyx, as in certain Cobseas and some Asclepiada- 

 ceous plants. The corolla is also, in the majority of flowers 

 which possess odoriferous properties, the seat of those odours. 



It is sometimes smooth, but very frequently its surface 

 bears hairs of various forms and colours, particularly in those 

 flowers which are pollinated by insects. Petals are frequently 

 narrowed below into ti, stalk-like portion, which corresponds 

 to the petiole of the leaf, as in the Wallflower and Pink (fig. 301) ; 

 the narrow portion is then termed the unguis or claw, o, and 

 the expanded portion the llmh, I, and the petal is said to be un- 

 guiculate or clawed. In this particular, petals must be con- 

 sidered to resemble the foliage leaves more than the sepals do, 

 as the latter organs are almost without exception sessile, or 

 destitute of claws. 



The outline of the petals, like those of the sepals and leaves, 

 is subject to great variation. They may be linear, oblong, 

 lanceolate, elliptic, ovate, cordate, &c. The application of these 

 terms having been already fully explained when speaking of 

 leaves, need not be further alluded to. The condition of their 

 maroins also, the manner in which they are divided, and their 

 terminations, are also indicated by the same terms as those 

 which we have already made use of in describing foliage 

 leaves. Thus the petals may be dentate, serrate ; cleft, partite. 



