16 



foreign plants unknown in any other town of the county, 

 and perhaps not elsewhere established. 



Two or three plants observed along the shore of the 

 Merrimac river suggest a close connection with the mills 

 at Lowell and Lawrence, one of them being a southern 

 sedge. Many plants are emigrating eastward from our 

 western states, travelling as it were by rail. The Kud- 

 beckia Mrta, now quite common in fields hereabouts, ac- 

 cording to Dr. Pickering, did not reach Philadelphia 

 until 1826, and this vicinity until perhaps 1855. 



The latest arrival noticed (1878) is that of Eleusine 

 Indica, a weedy, oriental grass which is common at New 

 York city and Philadelphia. It has made its appearance 

 along the railroad tracks at the Pennsylvania Pier, 

 Salem, having travelled thence by the P. and K. K. 

 R. Go's steamers, which regularly bring coal from Phila- 

 delphia. This last comes under the head of "ballast 

 plants," a very full account of which may be found in the 

 Torrey Bulletin for November, 1879. 



