72 VEGETABLE POWER OF ACCOMMODATION. 
The European cardoon, an esculent thistle, has broken out from 
the gardens of the Spanish colonies on the La Plata, acquired 
a gigantic stature, and propagated itself, in impenetrable 
thickets, over hundreds of leagues of the Pampas; and the 
Anacharis alsinastrum, a water plant not much inclined to 
spread in its native American habitat, has found its way into 
English rivers, and extended itself to such a degree as to form 
a serious obstruction to the flow of the current, and even to 
navigation. 
Not only do many wild plants exhibit a remarkable facility 
of accommodation, but their seeds usually possess great tenacity 
of life, and their germinating power resists very severe trials. 
Hence, while the seeds of many cultivated vegetables lose 
their vitality in two or three years, and can be transported 
safely to distant countries only with great precautions, the 
weeds that infest those vegetables, though not cared for by 
man, continue to accompany him in his migrations, and find 
a new home on every soil he colonizes. Nature fights in 
defence of her free children, but wars upon them when they 
have deserted her banners and tamely submitted to the domin- 
ion of man.* 
Indeed, the faculty of spontaneous reproduction and perpetu- 
ation necessarily supposes a greater power of accommodation, 
within a certain range, than we find in most domesticated 
plants, for it would rarely happen that the seed of a wild plant 
would fall into ground as nearly similar, in composition and 
condition, to that where its parent grew, as the soils of different 
fields artificially prepared for growing a particular vegetable 
are to each other. Accordingly, though every wild species 
affects a habitat of a particular character, it is found that, if 
* Tempests, violent enough to destroy all cultivated plants, frequently 
spare those of spontaneous growth. I have often seen in Norther Italy, 
vineyards, maize fields, mulberry and fruit trees completely stripped of their 
foliage by hail, while the forest trees scattered through the meadows, and the 
shrubs and brambles which sprang up by the wayside, passed through the 
ordeal with scarcely the loss of a leaflet. 
