97 



County, unless our knowledge of more stations there than else- 

 where is due to the very acute observations of Mr. Pretz and his 

 vigorous collecting. However, it can be asserted with confidence 

 that no botanist in the Philadelphia area (where S. arvensis is a 

 rare species) could possibly overlook a plant with such large and 

 bright yellow heads. Its handsome bloom or the striking 

 display of color when in quantity have invariably attracted its 

 collectors. 



From its occurrence in some cases in cultivated fields it is quite 

 generally supposed to have been introduced with foreign seed. 

 Its native region appears to be extreme eastern Europe and 

 adjacent Asia — in general, the area between the Caucasus, Ural, 

 and Altai regions. Mr. Pretz has communicated with the Office 

 of Seed and Plant Introduction of the United States Depart- 

 ment of Agriculture regarding the possible importation of seed 

 from this Old World area for sale or introduction. It was learned, 

 through Mr. S. F. Blake, that a good deal of Alfalfa seed has 

 been imported from the Caucasus region in recent years.* 5. 

 uliginosus has been found with Alfalfa in some places, but 

 Red Clover, Alsike, and various other plants of cultivation have 

 also been noted as associates, Mr. Pretz informs me, so that its 

 occurrence with Alfalfa has not been sufficiently marked or 

 distinctive to make it obvious that this has been the carrier. 



Except in the Allentown region, the stations are certainly so 

 scattered and far apart that it would seem they can scarcely 

 represent dissemination from a single station — as by natural 

 seeding. The immediate sources of most of these stations, if 

 not quite independent, might well be related to some large 

 grain or seed importation, rather well distributed, which con- 

 tained the weed seeds of the Sonchus. Introduction with imported 

 seed seems a reasonable surmise but it must be confessed that 

 this somewhat general belief is substantiated in most cases by 

 little or no detailed evidence. Regarding the origin of the station 

 near Quakertown, an acceptable view is advanced by Rev. 

 Creasey. The plant occurs beside a grist-mill, which fact is 

 certainly significant. But this in turn leads us to ask where 

 was grown the grain with which the weed seeds came to the 

 mill, and whence did the farmer originally obtain his seed- 

 grain? 



* Blake, Science, Iv. 455 (1922). 



