ORGANS OF REPRODUCTIO>-. 353 



That the hract is closely allied to the leaf, is evident from its 

 structure, form, colour, and from the development of one or more 

 buds in its axil. In order to be perfectly convinced of this ana- 

 logy, let any one examine the Foxglove, the Lilac, or the Pseony, 

 and then it will be evident that all stages of transition occur 

 between leaves and bracts, so that it wiU be impossible to doubt 

 their being homologous parts. 



That the sepals are homologous with leaves, is proved, not only 

 by their colour, &c., but also by the fact, that many flowers ex- 

 hibit in a natural condition a gradual transition between sepals 

 and bracfs, and the latter, as already noticed, are readily re- 

 ferrible to the leaf as a type. Thus in the Camellia, the transi- 

 tion between the sepals and bracts is so marked, that it is 

 almost impossible to say where the latter end and the former 

 begin. In the Marsh Mallow {fig. 372), and Strawberry {fig. 

 373) again, the five sepals in the flowers of the two respectively, 

 alternate with five bracts, and the difiiculty of distinguishing 

 them is so great, that some botanists call both set of organs by 

 the name of sepals. In many flowers in a natural condition 

 therefore, there is a striking resemblance between sepals and 

 leaves; and this analogy is at once proved to demonstration by 

 the fact, that in monstrous flowers 

 of the Rose, Primrose {fig. 761), 

 &c., the sepals are frequently con- 

 verted into true leaves. 



We now pass to the petals, and 

 although these in the majority of 

 flowers, are of a different colour 

 to leaves and the parts of the 

 flower which are placed external to 

 them, yet in their flattened charac- 

 ter and structure they are essentially 

 the same ; and their analogy to leaves 

 is also proved in many natural flow- 

 ers by the gradual transitions exhi- Fig. 761. Monstrous Piimrose, 

 i_. J , ^ ^ ^, , ^, , with the scuaU converted into 



bited between them and the sepals. true leaves. FromLindiey. 

 This is remarkably the case in the 



White AVater-Lily {fig. 438); also in the Magnolia, Calycun- 

 thus, &c., Avhere the flowers present several whorls of floral 

 envelopes, which so resemble each other in their general appear- 

 ance and colour, that it is next to impossible to say where the 

 sepals end and the petals begin. In many other cases also, there 

 is no other way of distinguishing between the parts of the calyx 

 and those of the corolla than by their ditferent positions, — the 

 calyx being the outcT series, the corolla the inner. The analogy 

 between petals and leaves is still further shown by the fact, that 

 the former are occasionally green, as in a variety of Kanunculus, 

 and in one of Campanula rapunculoides ; and also from their being 



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