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MW YORK 

 jTANJCAL 



TORREYA 



Vol. 22 No. 6 



November-December, 1922 



SONCHUS ULIGINOSUS OCCURRING IN THE 

 PHILADELPHIA AREA 



By Bayard Long 



In the autumn of 191 7, an unfamiliar Sonchiis was detected 

 along a railroad embankment near AUentown, Pennsylvania, 

 by Mr. Harold W. Pretz, in the intensive exploration of Lehigh 

 County which he has been carrying on for some years. A 

 specimen was sent to the Philadelphia Academy with his annual 

 contribution of material. The plant was far advanced into 

 maturity, with only a few fresh heads and no achenes, but it 

 was easily seen to be a form not commonly recognized in our 

 flora. It was evidently not closely allied to our two common 

 annual species of Sow Thistles, S. asper and S. oleraceus, but 

 from its foliage and several inches of stout root, increasing in 

 diameter to the broken end, it at once suggested a relationship 

 with the perennial 5". arvensis — from which, however, it appeared 

 to differ in several points, the most striking of which was its 

 glabrous involucres and pedicels. In 1918 another station was 

 discovered, and with each succeeding year additional material 

 of the plant has been coming to hand from new stations in our 

 local area. During the season of 1921 there was a greater 

 number of collections made, from areas more widely separated, 

 than in any previous year — in fact almost as many as from 

 1917 to 1920. 



We have learned, therefore, of a sufficient number of stations 



to show its presence in several counties of two states, and have 



enough intimate data on its occurrence to be reasonably certain 



of its actual status in our flora — particularly that it is not a 



mere casual appearing only in grass- or grain-fields (as so many 



of our new introductions). There is adequate information 



p-_, accumulated, it is believed, to indicate that this new weed is 



^^ becoming exceptionally well established and promising to be a 



"^ conspicuous and permanent element in our introduced flora. 



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