WEED MIGRATION 747 



Coulter, with the statement " sparingly introduced in Vermont, 

 Ontario, and Illinois. " It is not recorded in the fifth edition of the 

 same work by Dr. Gray in 1867. In the Britton Manual, 1901, 

 the distribution is given as Ontario, Vermont, and northern New 

 York, adventive from Europe, native also of Asia. According to 

 the Robinson and Pernald Edition of Gray's Manual (7th. Ed.), 

 1908, it had become so common because of its cultivation and "lo- 

 cally established as a weed" that the distribution was not given. 

 The writer saw it in abundance as a weed in Denver and Ft. Collins, 

 Colorado, and Salt Lake, in 1902, and in Chicago the same year. It 

 has been spontaneous as a weed in Ames since the year 1900. It 

 has been observed in Ames, Council Bluffs (1901), Sioux City 

 (1902), Cedar Rapids (1905), LaCrosse, Wis. (1904). The fol- 

 lowing catalogue of plants lists the species: Rydberg, Colorado, 

 at Fort Collins. 



COMPOSITAE, SUNFLOWER FAMILY. 



Prickly Lettuce {Lactuca scariola). 



This species was abundant in Utah in 1898 and was observed in 

 many parts of California the same year, but was, however, far 

 less common in the east. It was first observed in central Iowa, 

 Ames, in 1909 and now occurs in Ft. Dodge, Boone and Des Moines, 

 and is rapidly spreading. It is common in dry places in the Rocky 

 mountains and on the Pacific coast. Robinson and Fernald state, 

 "Roadsides, railway ballast, etc., New England to Oregon, N. W., 

 and Kentucky, chiefly westward, but even then less common than 

 the following variety (var. integrate/,). " It is common in northern 

 and central Ohio, Indiana and Illinois (DeKalb, Fox, Aurora, 

 Geneva, Chicago and Wheaton). 



Prickly Lettuce (Lactuca scariola var. integrata) . 



Waste grounds, roadsides and fields from the Atlantic to the 

 Pacific, especially northward. This is the form commonly referred 

 to by botanists when speaking of the weed in the east. This variety 

 was first reported by Dr. Gray. Specimens were collected by Mr. 

 D. Murray in 1863 and 1864; some specimens were collected by 

 M. S. Bebb at Rockford, Illinois, in 1879, and about the same time 

 by Mr. Henry Eggert in St. Louis. In 1883 it was common in the 

 vicinity of Madison but had not reached La Crosse, Wisconsin. 

 In 1886 a few specimens were reported in the vicinity of Onalaska 



