HorticuHural Sodiety of London. IBS' 



this day not a single instance can be adduced of any exotia 

 plant whatever possessing greater {^oivers of withstanding 

 cold, than it ha4 when first introduced. It has been hoped 

 thatji'fth^ seed^ of a given plant could be procured, for 

 many generations, in a climate severer than its own, the 

 offspring so obtained would gradually accommodate them- 

 selves to their new country ; but no such result has followed 

 from the experiments that have been tried. Let ua take a 

 fey?" familiar examples: — the common nasturtium, (Tropae- 

 luhi majus,^ a native of Peru, is said to have been intror 

 duced about the year 1686. At the time at which we are 

 writing, it must have descended through about 140 genera- 

 tions; and yet it has not become in the smallest degree 

 capable of resisting cold. Of the mignonette (Reseda odo- 

 rata), the date of introduction is not well ascertained ; it 

 has probably been a favourite border annual for sixty or 

 seventy years, and yet it has in no degree shaken off its annual 

 character, which is unnatural to it, and resumed the suffru- 

 tescent habit which it possesses in its own milder climate. 

 The potato, too, which has for two centuries and a half 

 been increased in every conceivable manner, by seeds as 

 well as by offsets, bears cold in no degree more readily 

 than it did in the sixteenth century. Nor does it appear to 

 us probable, that acclimatizing, if practicable, is to be 

 brought about by sowing seeds in northern latitudes through 

 successive generations. We do not believe that plants will 

 bear their seeds at all in a temperature much lower than 

 that in which they have been located by the hand of Nature. 

 The heat of a northern summer sufficiently approximates to 

 that of the tropics, to be considered, with reference to vege- 

 tation, as the same, and it is during that season that the 

 seeds of all plants are ripened ; the conditions, therefore, 

 under which the seeds of Tropaeolum, for example, are pro- 

 duced in England, do not materially differ from those under 

 Which the same seeds are produceu in Peru ; if the season 

 proves unpropitious in any considerable degree, they are not 

 produced at all. How then can it be expected that seeds 

 ripened under similar circumstances, but in different lati- 

 tudes, should give birth to a progeny differing in any re- 

 ma^'kable particular from their parents ? In fact, in power of 

 reslstlhg coW, they do not differ at all. If such a capability 

 were l^o be obtained, it would be by inducing plants to ripen 

 their seeSs in winter. 



But if it is certain that nothing is to be gained in acclima- 

 tiring, by raising plants from eeed through successive gene^. 



