Horticultural Society of London, l71 



arranged in divisions depending upon the size of the plants 

 and the colour of their flowers. We do not propose to analyze 

 this paper, which is far too extensive for our limits; but in- 

 steaa, to throw together a few remarks which are suggested 

 by the subject. 



The first Ikct to which we would call attention has reference 

 to Acclimatization. The Dahlia has now been cultivated in 

 Europe with the utmost assiduity for nearly thirty years. Du- 

 ring tnat period millions of plants have been raised from seeds, 

 and under almost every possible variation of climate; and ano- 

 Irialie^ the niost singular, not only in colour, but in general 

 Constitution and physiological structure, have been obtained. 

 The colour of the nower has been altered from pale yellow, 

 or lilac, to every hue of red, purple, or yellow, to pure 

 scarlet and to deepest morone, or has even been wholly dis- 

 charged from the radial florets in the white varieties; the 

 period of flowering has been accelerated nearly two months ; 

 the tall rank weed, exceeding the human standard in height, 

 has been reduced to a trim bush, emulating the paeony in 

 dwarfishness ; the yellow inconspicuous florets of the disk 

 have been expelled to make room for the showy deep-coloured 

 florets of the ray ; what is more remarkable still, the same 

 yellow inconspicuous florets of the disk have been enlarged, 

 and stained with rich morone, so as to rival the colours of the 

 ray without losing their own peculiarity of form ; and finally, 

 the v/hole foliage and bearing of the plant has been altered 

 by the substitution of simple leaves for compound ones. But 

 notwithstanding all this proneness to change, notwithstand- 

 ing the multitude of varieties which have been thus procured 

 by seed, not one individual has yet been discovered^ in any 

 degree whatever ^ more hardy than its ancestors. The earliest 

 frosts destroyed the Dahlias as certainly in 1826, as they could 

 have done in 1780. 



But, however strong may be the disposition of the Dahlia 

 to vary from its original structure, it is curious to observe 

 how strictly it conforms to the laws by which such variations 

 are controlled by nature. In altered structure all the changes 

 take place from circumference to centre. The florets of the 

 ray displace those of the disk, but the latter never attempt 

 to occupy the ray ; when a change occurs among the florets 

 of the disk, they merely dilate and assume the colour of the 

 ray, without changing their position or their peculiar form. 

 So with the leaves; by a reduction of the lateral leaflet, till 

 the terminal one only remains, simple foliage is substituted 

 for that which was compound : but no case has been found in 



