HISTORY OF PLANTS. 333 
fall to the ground, and their juicy integuments pre- 
sent the necessary food to the young plants. Se- 
veral birds and other animals feed on them, carry 
them off, tear the fleshy part, and thus drop the 
seeds, or these pass indigested through their intes- 
tines, and thus are spread abroad. In this manner 
Viscum a/bum is propagated by a bird, Turdus 
viscivorus, and Juniperus communis, and others in like 
manner. 
Man, however, more than wirid, weather, seas, 
rivers and animals, contributes to the dissemination 
of plants. He who commands nature, who changes, 
deserts into beautiful landscapes; lays waste whole 
countries, and again brings them to their former 
state, has in various ways favoured the distribution 
of anumber of plants over our globe. 
The wars in which different natiohs have been en- 
gaged, the migrations of nations, the crusades, the 
travels of different merchants, and commerce itself 
have brought a number of plants to us, and trans- 
planted ours into foreign countries. Almost all our 
culinary plants come from Italy of the East, as well 
as most species of corn. Since the discovery of 
America, likewise, we have got several vegetables, 
whiéh formerly were not known, but now are uni- 
versally spread over Europe. 
The common thorn apple, the Datura Stramoniun:, 
which now grows almost throughout all Europe, the 
colder Sweden, Lapland, and Russia excepted, 
and is thrown out asa noxious weed, came from 
the East Indies and Abyssinia to us, and- was so tini- 
Bb 3 versally 
