92 



In the course of identifying this plant and making comparisons 

 with otlier material, it became obvious that we had to do with 

 a close ally of 5. arvensis var. glahrescens, which had been re- 

 corded some years previously in America by Fernald and Wie- 

 gand.* It seemed that this form should be merely a glabrous 

 extreme of S. arvensis, differing only in the lack of glandularity 

 on the pedicels and involucral bracts — as correctly interpreted 

 by the critical judgment of these authors. The plant of im- 

 mediate concern introduced in the Philadelphia area differed 

 from a glabrous phase of S. arvensis in the larger inflorescence 

 of more numerous heads, the narrower and more cylindric 

 involucres, the shorter and paler bracts, the (apparently) 

 larger heads. This plant matches well material of a species 

 allied to S. arvensis from the region about the Caspian Sea — 

 Sonchus uliginosus Bieb. Some European students, it may be 

 noted, have reduced Bieberstein 's species to S. arvensis var. 

 glahrescens Giinth., Grab. & Wimm.f but, although there may 

 be some doubt as to the specific distinctness of S. uliginosus, 

 it does not appear to be the same as the plant of Giinther, 

 Grabowski and Wimmer.J 



Of the half-dozen collectors who have met the plant all have 

 furnished intimate accounts of the stations known to them. 

 Mr. Pretz has been the most fortunate in seeing it many times. 



* Fernald & Wiegand, Rhodora, xii. 145 (1910). 



f Mr. S. F. Blake has called my attention to the fact that the name Sonchus 

 arvensis var glahrescens was first published by C. Giinther, H. Grabowski, and 

 F. Wimmer, Enum. Stirp. Phan. Siles. p. 127. 1824. It is described as 

 *' Sonchus arvensis . . . B. glahrescens nob. pedunculis calycibusqiie 

 glabris. Bei Reinerz (Wiemann). Bei Einseidel in Gesenke. Aug. 11." This 

 is a rare volume. 



f Through the kind interest of Mr. C. A. Weatherby I have been enabled 

 to examine the bases of the records for 5. arvensis var. glahrescens by Fernald 

 and Wiegand, as well as certain later collections similarly referred. Of these 

 specimens at least two certainly appear to be the same as the plant here 

 identified with S. uliginosus: Dry roadside back of Sibley College, Cornell 

 University Campus, Ithaca, Tompkins County, New York, July 26, 1916, 

 K. M. Wiegand 7327; Near Soldiers Home, Erie County, Ohio, August 1902, 

 W, P. Holt. In view of our imperfect understanding of the relation of 5. 

 uliginosus to S. arvensis var. glahrescens, this determinative comment is ad- 

 vanced with considerable hesitancy and should be considered as only tentative 

 or suggestive for consideration by some student of the Cichoriaceae, 



