ACCLIMATIZATION, ETC. 275 



remarked on page 160, in connection with the lacquer tree, this 

 plant proved quite hardy enough to endure winters in Germany. 

 But in Japan it is found in the neighbourhood of, and cultivated 

 side by side with the camellia, Olea aquifolium, and other orna- 

 mental plants which are there sometimes exposed to night frosts 

 reaching — 12° C, but in Europe will not live out of doors north of 

 the Alps. 



As the Camphor-laurel is indigenous to a country having much 

 summer rain, and in winter undergoes night frosts in which the 

 mercury in the thermometer occasionally sinks to — 9°C., its thriv- 

 ing condition on the North Italian lakes and the Riviera is easily 

 comprehended. That it does well also in the hot, dry, atmosphere 

 of Egypt and the Canaries, shows its power of adaptation in a 

 direction in which not many Japanese plants can follow it. 



The grape vine thrives to a certain extent in many different 

 climates and soils, but how largely is the character of its fruit 

 changed thereby ! To take still another example, the varied con- 

 ditions of the poppy {papaver somniferum), whose capsules contain 

 with us only traces of the well-known opium alkaloids, while in warm 

 countries, like Asia Minor, Egypt, and India, it is cultivated solely 

 for its opium, which varies significantly in its chemical composition 

 according to the land which produces it. 



From these few examples, to which many more might be added, 

 it is satisfactorily shown that the ability of a plant to adapt itself 

 is much greater than its full acclimatization, if we understand by 

 the former the thriving in changed climate and soil without de- 

 generation, i.e., without essentially altering its original character. 



Annuals acclimatise themselves easier than perennial plants. 

 This is an old experience and easy of comprehension. A number 

 of well known weeds have become scattered over a large part of 

 the earth with our garden and field fruits. They spread luxuriantly 

 in climates vastly different from ours, as do many of our grains and 

 vegetables, for the main thing with them is, next to a certain degree 

 of moisture, the presence of sufficient warmth to ripen their seeds. 



With wood growths the matter is more complicated. Their 

 perfect acclimatization depends on both of the principal seasons of 

 the year, and much more on the extreme than the middle tem- 

 peratures. They must at least prove themselves hardy against the 

 winter's cold. Their power to withstand unusual cold is conditioned, 

 partly on the full ripening of their wood in autumn, and that 

 vegetation shall not at this season receive a fresh impulse from 

 unusual heat. For when this happens, a new circulation of the sap 

 begins, the preparation for winter is lost, and the plant consequently 

 can endure but little. It finds itself then in the condition of a 

 animal in northern regions without its winter coat. Therefore one 

 cannot condemn a plant as not adapted to cultivation because it 

 succumbs to unusual cold, coupled with other unfavourable pre- 

 liminary conditions. No one will maintain that rape or clover are 



