SOME RFXENTLY INTRODUCED WEEDS. 17 



other species from the prairies or beyond — such as the buffalo 

 bur (Solanum rostmtum) and its near relative the horse nettle 

 {Solanum carolinen.se) are creeping more and more into New- 

 England ; but compared with the Old World species these 

 American plants are usually unimportant weeds. 



Many plants at the time of their first introduction into 

 America seem harmless and unlikely to cause trouble ; but after 

 a period of acclimatization on the dumping grounds or in the 

 undisturbed fence corners they suddenly reach a period of active 

 reproduction, and in their offspring the aggressive qualities which 

 class them as weeds are suddenly developed. Thus in 1863 a 

 few plants of rape {Brassica campestris) were known to occur at 

 Buffalo, but as late as 1882 the species though persisting was 

 barely established. In 1887, however, it began to be troublesome 

 in fields of central and western New York, and in 1888 it was 

 common on dumps and rubbish heaps in eastern Massachusetts. 

 Then it suddenly appeared as a weed of grain fields and other 

 cultivated grounds throughout New England and eastern Canada 

 where it is still a common nuisance. The blueweed or viper's 

 bugloss {Echium vulgare) was known as an occasional waif on 

 dumps or by neglected roadsides for nearly fifty years before it 

 began, within the last quarter-century, to take a strong foothold 

 in dry fields and cultivated land through eastern New York and 

 New England. 



On the other hand, some plants, which, in the past, have borne 

 hard reputations, seem to have run their course and to have set- 

 tled to a less aggressive mode of life. The henbane {Hyoscj/amns 

 niger) , a disagreeably sticky and ill-smelling weed, which early 

 Massachusetts botanists considered common, has now })ractically 

 vanished fi-om the New England flora, though it is abundant in 

 eastern Quebec. Indeed, there seems good reason to assert that 

 even the prickly lettuce {Lactuca scariohi, var. ijitegnfta), 

 which for years has been the bete noir of the western farmers, is 

 now on the wane. But even though we mav hope that all the 

 weeds which are brought to us from foreign lands will eventually 

 become as innocuous as the once common henbane, tlie ])rospect 

 of waiting for 600 species and their successors to run their full 

 course is not a pleasing one ; and some energetic methods must 

 be employed to check the progress of new weeds. 



