WEED MIGRATION 745 



northwestern Iowa, northeastern Nebraska and western Minnesota. 

 In 1898 it was reported from Colorado, Wisconsin, Illinois and 

 other western states. In 1894 Pammel gave the following account 

 of its distribution: 



Prof. Dewey 's map indicates that the badly infested area extends 

 from the east bank of the Missouri river at Bismarck to Jamestown 

 and Moorehead in North Dakota; south to Sioux City, in Iowa; it 

 also occurs in many isolated places in Minnesota, Wisconsin, Iowa, 

 and at Denver, Colorado. The localities at which he found it in 

 Iowa are Rock Rapids, Emmetsburg, Spencer and west to the 

 Missouri river, Council Bluffs, and on the Missouri river opposite 

 Nebraska City. To these we must add Edna, Ames, Little Rock 

 (Ball), Calumet (Louthan), Missouri Valley, Mason City, Eagle 

 Grove, and in all probability it occurs along our great trunk lines 

 across the state. Last season Mr. 0. W. Carver found a small 

 specimen of what undoubtedly was Russian thistle along the Chi- 

 cago & Northwestern railroad; the place was revisited this year, 

 and an abundance of the weed was found. A few days later 

 Messrs. Robt. Combs and C. B. Weaver found several localities 

 between Ames and Ontario, and Mr. Sheldon reported it in the 

 Ames stock yards. As to its probable early appearance in Iowa 

 we have reliable data. Prof. A. S. Hitchcock, an excellent ob- 

 server and collector, reported it from Woodbury county in 1888, 

 and Mr. R. I. Cratty, of Emmetsburg, reported it from Emmet 

 county in 1890 or 1891. It has also been sent to me from Ellsworth, 

 in Nobles county, Minnesota, close to the Iowa line. Mr. G. W. 

 Carver found great quantities of it near Chicago, at Turner Junc- 

 tion, and J. J. McMahon from Peatone, Illinois. 



It occurred as early as 1890 in Wisconsin. The writer, in re- 

 cently looking over a collection of specimens made in the vicinity 

 of Prairie Du Chien, in 1890, found a specimen of Russian thistle. 

 The species was growing in considerable quantity along the sandy 

 embankment of the river and railroad, not far from the railway 

 station. It is not unlikely that it spread eastward along the Chi- 

 cago, Milwaukee and St. Paul railroad for considerable distance. 



It now occurs in many Iowa counties, especially along railroads. 

 It is one of the most abundant weeds in western Nebraska, Colo- 

 rado, Utah, Montana and Idaho. It is more or less sporadic in its 

 appearance ; some years more abundant than others. It was espe- 

 cially common at many points in Iowa in 1910 and 1911. Its dis- 

 tribution in Iowa as reported from time to time is as follows : Post- 

 ville, 1894 (Orr) ■ Mason City and Eagle Grove, 1894 (Pammel) ; 

 Muscatine, 1894 (Reppert) ; Boone, 1895 (Carver) ; Ames, 1895 

 (Rolfs) ; Hawarden, 1895 (Pammel) ; Missouri Valley, 1897 (Pam- 

 mel) ; Ledges, 1898 (Pammel) ; Armstrong, 1901 (Cratty) ; Ogden, 



