CITIZENSHIP OF PLANTS. 395 
both. It is now a native of both countries, but there may have 
been a period when it existed in neither. 
Let another plant, say the common Apple-tree, be assumed. 
This, it is also well known, is about equally common in both 
France and England. Yet there is in this case a greater proba- 
bility that it may have existed in France previously to its ap- 
pearance in England; and if this be granted, there is a greater 
probability that it owes its propagation in this country to human 
means, than that its immigration was the result of accidental 
causes. If its original locality be neither the north of France 
nor the south of England, it is probably an introduced plant. 
Botanists fix its centre of distribution in a more southern loca- 
lity than either of these two localities. As cultivation amelio- 
rated the climate, its range has extended, especially to the north 
and the west. It may, with many other plants, be still widen- 
ing its extent of radiation from its original home, if it ever was 
limited to a small tract in the centre of its present range. But 
this is a fact incapable of proof. We can prove that certain 
plants are acquiring a wider range; but can we prove that they 
originally proceeded from a single plant or from a single pair, or 
from a very limited space? We strongly suspect that this is 
incapable of proof. The Crab, or Wild Apple-tree, is far from 
uncommon in the southern and central parts of England, but it 
is scarce in Scotland. This fact indicates a more southern cen- 
tre of distribution than even England; yet it does by no means 
satisfactorily prove that it is not native in Scotland. It may he 
suspected that the terms native or indigenous, as applicable to 
plants, are not received even by botanists in the same sense. 
A spontaneous production is held to be native by some. A 
plant established a thousand years will seldom have its na- 
tivity challenged. Again, a widely distributed plant is usually 
considered indigenous. The Apple-tree is called a native, the 
Pear-tree has at best but doubtful claims to this distinction ; 
yet they are both distributed over the same countries, and can 
both bear nearly the same atmospheric changes. The Apple- 
tree is only rather more plentiful, or more examples in a wild 
condition are found; it is also in the occupation of a greater 
range. Here it extends from the south to the north of Eng- 
land, being very rare in a wild state in Scotland. The Pear- 
tree is not of so frequent occurrence as the Apple-tree is; fewer 
