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Irregular Metamorphoses of flowers are extremely common, and usually consist 

 either of an actual multiplication of petals, or of the transformation of stamens and 

 pistils into petals ; the effect of these changes being the formation of double flowers, 

 the impletion of which appears to take place in different ways in different plants. In 

 most Icosandrous and Polyandrous plants, impletion appears to result almost entirely 

 from the conversion of the stamens, and in some instances of the pistils, into petals ; 

 in the double varieties of Ulex europceus it results from the same change. In Oligan- 

 drous plants we usually find an actual multiplication of petals ; as may be seen in the 

 double stocks and wallflowers of our gardens. Where the impletion is the result of 

 this alteration of the essential floral organs, the plants are necessarily barren. Such, 

 however, is not the case with the Dahlia, Aster, and other plants which belong to the 

 Corymbiferous section of Compositae ; in these the impletion results, first, from the 

 change of the tubular florets of the disk into ligulate florets, the same as those of the 

 ray, as in the Dahlia, and, secondly, by the simple enlargement and elongation of the 

 tubular florets, as in the many varieties of the China Aster. Such monstrosities, from 

 the fact of the essential organs not being in any way implicated, are capable of per- 

 fectly impregnating their ovules. Thus a knowledge of the mode in which impletion 

 occurs, is of importance to the gardener, in order that he may be enabled to calculate 

 on the possibility of producing new varieties by seed. 



Dr. Lindley says that " these changes always occur in the order of development, or 

 from the circumference to the centre ; that is to say, that the calyx is transformed into 

 petals, petals into stamens, and stamens into ovaria ; but that the reverse does not take 

 place." In proof of this hypothesis he further says " that if the metamorphosis took 

 place from the centre to the circumference, or in a direction inverse to the order of 

 development, it would not be easy to show the cause of the greater beauty of double 

 flowers than of single ; because the inevitable consequence of a reversed order of trans- 

 formation would be that the rich or delicate colour of the petals, upon which all flow- 

 ers depend for their beauty, would be converted into the uniform green of the calyx. 

 Such a change therefore, instead of increasing the beauty of a flower, and making it 

 superior to its original, would tend to destroy its beauty altogether." Now were this 

 hypothesis correct, and founded on fact, what ought to be the condition in which we 

 find the organs in double flowers ? We ought surely to find the centre of the flower 

 filled up with an increased number of pistils. But is this the case ? It is plain it is 

 not ; indeed, were it the case, the beauty of a double flower would be most effectually 

 destroyed. This theory must therefore fall to the ground, and we must confess that 

 we are unable to find any laws by which the order of ti'ansmutation, in such monsters, 

 is governed. 



The aim and object with the cultivators of double flowers, is to convert all the flo- 

 ral organs into petals, and we generally refer to cultivation as the cause of flowers be- 

 coming double ; farther than this we are ignorant of the causes of their impletion. — 

 They probably owe their origin, at first, to accidental circumstances, and afterwards 

 the variety is carefully propagated by the methods usually adopted for that purpose. 



The two classes of vegetable functions, namely, the vegetative and reproductive, 

 notwithstanding their close connexion, appear to be performed, in some degree, in op- 

 position the one to the other ; thus any excessive development of the one class, takes 

 place at the expense of the other. — T. S. 



