The first fact 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. During that period millions of plants have been raised from seeds, and under almost every possible variation of climate; and anomalies the most singular, not only in colour, but in general constitution and physiological structure, have been obtained. The colour of the flower 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 discharged 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 pæony 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 whole 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, notwithstanding 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 1789.