146 DISSEMINATION OF SEEDS. 



from Mexico, La Plata, and Buenos Ayres to Europe. 

 In the process of cleaning these fall out and often spring 

 up in the new soil. This has been noticed particularly 

 at the port of Montpellier where American wools are re- 

 ceived to be purified ; here the seeds of many American 

 plants have sprung up and obtained possession of the 

 soil. Dr. Shaw mentions the similar introduction of a 

 European plant, Xanthium spinosum, into South Africa ; 

 its spiny achenia cling to the wool of Merino sheep. 



Many plants now naturalized here have been brought 

 as garden plants, others have been found in the materials 

 used for packing merchandise brought from foreign coun- 

 tries, and others have been brought with the materials 

 used for new manufactures. As an instance of the last 

 named may be mentioned the introduction into Tapley- 

 ville, in the vicinity of a carpet factory, of several species 

 of foreign plants. 



In the ballast in vessels sailing from many parts of the 

 world, the seeds of foreign plants are often found and 

 these springing up increase the number of plants not 

 natives of the soil. 



In the "Flora of Essex County," lately published by 

 Mr. .Robinson, one can find the names of many plants 

 thus introduced into this country. In this, it is stated 

 that the latest arrival noticed is Elemine Indica, a weedy 

 oriental grass common in New York and Philadelphia. 

 It has made its appearance along the railroad tracks at 

 the Pennsylvania Pier, Salem, having travelled thence by 

 the steamers which regularly bring coal from Pennsylvania. 



America has sent to Europe only a very few weeds. 

 Dr. Seemann says this is because our present flora is older 

 than the Germanic flora which now constitutes the prin- 

 cipal vegetation of Europe. America and Australia have 

 not attained to the degree of floral development to which 



