212 COLI^ CLOUT'S CALENDAR. 



uriance. Sucli facts as these we all know and expect ; 

 it seems fit and proper that the familiar weeds of culti- 

 vation should follow civilized tillage on its widening 

 way over the world. But we are more surprised when 

 we find that a good many American weeds have also 

 forced their way eastward against the stream, so to 

 speak and have invaded the Old "World, en revanche, 

 with the potatoes and the maize, achieving such success 

 as to have lived down more than one of their European 

 compeers. In southern France and Italy the number of 

 these eastward immigrants is very considerable ; and 

 even in wetter and chillier England, a poor foster- 

 mother for children of the basking American plains, it is 

 far from being either small or unnoticeable. Such 

 cases are not in themselves at all more remarkable than 

 those of the phylloxera, which has already made good 

 its footing in Europe, or of the Colorado beetle, which 

 we are now endeavoring feebly to repel ; but they seem 

 more curious at first sight, because the aggressiveness of 

 fixed and unconscious plants is harder to understand than 

 the aggressiveness of locomotive and volitional animal 

 organisms. 



Two of these American wood-sorrels, both with yellow 

 flowers, have now made themselves a permanent home 

 in England, and have even conquered their admission 

 within the exclusive lists of the British flora. One of 

 them has long been a universal weed in all hot climates 

 of the globe and in most temperate ones, having followed 

 the tobacco-plant to Syria and Java and accompanied the 

 tomato to all the warmer climates of Mediterranean 

 Europe. In England it appears chiefly in the southern 

 counties, and does not thrive well in the midlands or 

 the north. But some other American weeds have had 

 better luck among us ; such, for example, as the tiny 



