The Flora of the Cayuga Lake Basin 429 



The Mack farm s. of Ithaca (D.) ; near Coy Glen; various streets in Ithaca 

 (D.) ; C. U. campus, in several places; Renwick; Myers Point (D.) ; Sheldrake 

 (D.) ; Union Springs (D. !) ; Cayuga (D.) ; about Salt Pond w. of Howland Island; 

 and elsewhere. 



Newf. to Minn, and B. C, southw. to N. J., Colo., and Utah. Naturalized 

 from Eu. 



A difficult weed to eradicate. Dudley gives interesting historical facts regarding 

 its introduction in N. Y. State. 



la. S. arvensis L., var. glabrescens Wimm. & Graeb. (See Rhodora 12: 145. 1910.) 



In situations similar to the preceding; frequent. July-Sept. 



C. U. campus, near the baseball cage and back of Sibley College ; s. of Renwick, 

 and near the Renwick Park (Stewart Park) buildings. 



Occasional in e. N. A. 



Bayard Long (see Torreya 22:91, 1922) considers the Sibley College specimens 

 to be 5". uliginosa B'ieb. The other local specimens with glabrous involucre were 

 not seen by Long, but they are all similar to the Sibley College specimens. They 

 seem to differ somewhat from typical S. arvensis in the characters given by Long, 

 and he may be correct in considering them as specifically distinct. 



2. S. OLERACEUS L. COMMON SOW THISTLE. 



A weed in waste places and cultivated fields, in rich soil ; common. Aug.-Sept. 

 Generally distributed as a weed over most of the earth, except in the extreme 

 North. Naturalized from Eu. 



The leaf outline varies greatly, the more extreme types being as follows: 



(a) The typical form : terminal division of leaf broadly triangular, lateral 

 divisions present ; common. 



(b) Forma triangularis (Wallr.) G. Beck: terminal division of leaf broadly 

 triangular, lateral divisions wanting ; near the salt works, Ithaca flats. 



(c) Forma laccrus (Willd.) G. Beck: terminal division of leaf narrow; athletic 

 field, C. U. campus ; Highland Ave. ; Cayuga Heights ; West Hill, near the L. V. 

 R. R. station ; Ithaca flats, near the salt works. 



3. S. asper (L.) Hill. Spiny-leaved Sow Thistle. 



In situations similar to the preceding ; common. Aug.-Sept. 



Distribution similar to that of the preceding species. Naturalized from Eu. 



46. Lactuca (Tourn.) L. 



a. Leaves with prickly midrib and margins. 



b. Leaves pinnately lobed. 1. L. scariola 



b. Leaves not lobed. la. L. scariola, 



var. integrata 

 a. Leaves not prickly. 



b. Flowers yellow; achenes distinctly slender-beaked, 1-nerved on each face. 

 c. Involucre 16-22 mm. long ; achenes 7-9 mm. long ; pappus 9-12 mm. long ; 

 leaves sparingly and coarsely setose along the midrib, the lateral divisions 

 broadest above the base, often obliquely truncate at the apex. 



2. L. hirsuta 

 c. Involucre 10-14 mm. long ; achenes 5-6 mm. long ; pappus 5-7 mm. long ; 

 leaves usually glabrous, the lateral divisions broadest at base or apex, or the 

 leaves unlobed. 

 d. Leaves with linear-falcate, usually entire, lobes ; the upper unlobed leaves, 



if any, linear or linear-lanceolate. 3. L. canadensis 



d. Leaves with broadly falcate or obovate and obliquely truncate, entire or 



