68 f TENACITY OF LIFE IN WILD ORGANISMS. 
The Canada thistle, Erigeron Canadense , is said to have 
sprung up in Europe, two hundred years ago, from a seed 
which dropped out of the stuffed skin of a bird.* 
Vegetables , how affected by Transfer to Foreign Soils. 
Vegetables, naturalized abroad either by accident or design, 
sometimes exhibit a greatly increased luxuriance of growth. 
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 impen¬ 
etrable 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 how 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 tena¬ 
city of life, and their germinating power resists very severe 
trials. Hence, while the seeds of very many cultivated vege¬ 
tables lose their vitality in two or three years, and can be 
transported safely to distant countries only with great precau¬ 
tions, 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 
Hungary, and probable that they in some measure compensated the injury 
by introducing maize also, which, as well as tobacco, has been claimed as 
Hungarian by patriotic Magyars. 
* Accidents sometimes limit, as well as promote, the propagation of 
foreign vegetables in countries new to them. The Lombardy poplar is a 
dioecious tree, and is very easily grown from cuttings. In most of the 
countries into which it has been introduced the cuttings have been taken 
from the male, and as, consequently, males only have grown from them, 
the poplar does not produce seed in those regions. This is a fortunate cir¬ 
cumstance, for otherwise this most worthless and least ornamental of trees 
would spread with a rapidity that would make it an annoyance to the 
agriculturist. 
