474 ANNUAL REPORT 



seeds must have fallen from passing freight cars, and hosts of 

 others might be mentioned. 



Years ago it was a matter of common observation when farm- 

 ers hauled their grain long distances to some market that along 

 the road could be found Chess, Corn, Cockle, etc. It can still 

 be seen but in a less marked degree. 



MIGRATION OF WEEDS. 



Many of our most troublesome weeds are foreigners, as is made 

 apparent from the table at the end of this list. Many have be- 

 come so thoroughly naturalized that it is difficult to make a 

 line of separation of the truly indigenous (native) and those nat- 

 uralized. While we have added a large number of European 

 plants, Europe has received from us, such as the common Horse- 

 weed Erigeron canadense, the common Evening Primrose 

 Oenotherahiennis, and Anacharis canadensis a harmless North 

 America water plant, said to be so abundant in England 

 as to clog up canals. Some of our weeds which were at first 

 ballast plants along the seaports, have moved westward. Prickly 

 Lettuce Lactuca 8cariola, which was for many years an adven 

 tive in eastern New England, has since 1874 spread with remark- 

 able rapidity, and is now found in many of the states east of the 

 Mississippi river. Some western native plants have moved east- 

 ward and have become pernicious weeds. Solarium rostratum, a 

 native of Kansas and Southwest, has traveled eastward and has 

 been reported from New York. Of the less troublesome weeds 

 Worm Wood Artemisia biennis. Cone Flower BudbecMu hirta are 

 reported as common in the East and inclined to be weedy. 



In the arrangement of the orders and genera I have followed 

 Bentham & Hooker's Genera Plantar um. The nomenclature is 

 that given in Dr. Gray's Synoptical Flora of North America 

 (Gamopetalae), Watson's Bibliographical Index to North Ameri- 

 can Botany (Pt. 1 Polypetalae) and Botanical contributions by 

 Sereno Watson and Dr. Gray. 



The introduced weeds 9,re printed in italics. 



CRUCIFIRAE. 



Sisymbrium, officinale, Scoj). Hedge Mustard. Abundant in 

 waste places and has become naturalized from Europe. 



