456 
POPULAR BOTANY. 
surprised and annoyed on having the contents of this repulsive fruit 
thrown in their face. 
Finally, one of the most extensive distributions of seeds is effected 
by the commercial exchangs of grains. Through this channel we find not 
only the desirable supply of breadstuffs and the useful products of 
different climes exchanging localities, but also the undesirable varieties 
of noxious weeds and foul plants, surprising and annoying the gardener 
and farmer, who only bargained for a new variety of wheat or some 
other grain. The greater part of these so-called weeds, and many other 
plants growing in the vicinity of cultivated grounds, have been intro- 
duced in this way. It is, therefore, now difficult to determine which of 
these plants are of American or foreign origin. I shall never forget my 
surprise on finding, in the year 1818, in the vicinity of Cologne, such a 
variety of strange plants. The weather in the years 1816 and 1817 was 
so exceedingly w T et that no grain of any kind could come to maturity, 
on which account the government thought it prudent to import the 
necessary seed-grain from Eussia at government expense, in order to 
prevent famine, and with these grains a number of Russian plants were 
introduced to the vicinity of the Ehine. 
It is very interesting to observe with how much effort plants en- 
deavour to produce seed, or to propagate themselves in other ways ; for 
instance, in the case of plants whose flowering season in a natural state 
is only of a short duration ; if we pluck their flowers before they have 
matured their seed, the plants will persevere to flower again and again, 
as if never satisfied short of the full maturing of their seed, for succes- 
sion. In accordance with this principle, amateur gardeners keep most 
of their favourites almost constantly in bloom. 
As before mentioned, plants propagate themselves in many other 
ways than by the production of seed ; for instance, the weeping willow, 
the wild cotton tree, the weeping ash, &c. When their long pendant 
twigs reach down to the ground and are supported by the wet weather 
they take root, and by reaction the little twig becomes the trunk of a 
new tree. This tree, in its turn, elaborates the same process, until some- 
times, in wild uncultivated countries, a space of even several miles in 
extent is thus spontaneously produced from one original standard tree. 
The same occurs with some perennial plants, driving out runners ; 
for instance, our strawberries, ranunculus, Potentilla, &c. These plants 
send forth slender feelers, so far from the mother stock as not to inter- 
fere with each other, and then take root, and become independent 
plants. As soon as these young plants have attained a certain 
size, they also throw out their own feelers, and in this way we find often 
a considerable surface covered from a single plant. One of the most in- 
teresting of this kind of plants is the Saxifraqa stolonifera, a plant 
most commonly used for hanging pots. This plant which grows, as far 
as I can recollect, at the northern sides of the Italian Alps, will certainly 
